path: root/Documentation/user-manual.txt

// Subsurface 4.0.1 User Manual
// ============================
// :author: Manual authors: Jacco van Koll, Dirk Hohndel, Reinout Hoornweg,
// Linus Torvalds, Miika Turkia, Amit Chaudhuri, Jan Schubert, Willem
// Ferguson, Salvador Cuñat
// :revnumber: 4.0.1
// :revdate: December 2013
:icons:
:toc:
:toc-placement: manual
:numbered:
// :website: http://subsurface.hohndel.org

image::images/Subsurface4Banner.png["Banner",align="center"]

[big]#USER MANUAL#

*Manual authors*: Jacco van Koll, Dirk Hohndel, Reinout Hoornweg, Linus
Torvalds,
Miika Turkia, Amit Chaudhuri, Jan Schubert, Willem Ferguson, Salvador Cuñat

[blue]#_Version 4.0.1,  January 2014_#


Welcome as a user of _Subsurface_, an advanced dive logging programme with
extensive infrastructure to describe, organise, interpret and print scuba
and free dives.
_Subsurface_ binaries are available for Windows PCs (Win XP or later), Intel
based Macs (OS/X) and many Linux distributions. _Subsurface_ can be built for
many more hardware platforms and software environments where Qt and
libdivecomputer are available.

The scope of this document is the use of the _Subsurface_ program. To install
the software, consult the _Downloads_ page on the
http://subsurface.hohndel.org/[_Subsurface_ web site].
Please discuss issues with this program by sending an email to
mailto:subsurface@hohndel.org[our mailing list] and report bugs at
http://trac.hohndel.org[our bugtracker].  For instructions on how to build the
software and (if needed) its dependencies please consult the INSTALL file
included with the source code.

*Audience*: Recreational Scuba Divers, Free Divers, Tec Divers, Professional
Divers

toc::[]

[[S_StartUsing]]
Start Using the Program
-----------------------

The _Subsurface_ window is usually divided into four panels and has a *Main
Menu* (File Import Log View Filter Help) at the top of the window (for Windows
and Linux) or the top of the screen (for Mac and Ubuntu Unity). The four panels are:

1) The *Dive List* to the bottom left containing a list of all the dives in the
user's
dive log. A dive can be selected and highlighted on the dive list by clicking on
it. In most situations the cursor up/down keys can be used to switch
between dives.

2) The *Dive Map* to the bottom right, showing the user's dive sites on a world
map
and centred on the site of the last selected dive.

3) The *Dive Info* to the top left, giving more detailed information on the
selected dive, including some statistics for the selected dive or for all
highlighted dive(s).

4) The *Dive Profile* to the top right, showing a graphical dive profile of the
highlighted dive in the dive list.

The dividers can be dragged between panels in order to change the size of any of
the panels. _Subsurface_ remembers the position of the dividers, so the next
time _Subsurface_ starts it uses the positions of the dividers when the program
was executed previously.

If one dive is selected, the dive location, detailed information and profile of
the _selected dive_ are shown in the respective panels. On the other hand, if
one highlights more than one dive the last highlighted dive is the _selected
dive_, but summary data of all _highlighted dives_ is shown in the *Stats* tab
of the *Dive Info* panel (maximum, minimum and average depths, durations, water
temperatures and SAC; total time and number of dives selected).

[[S_ViewPanels]]

image::images/main_window.jpg["The Main Window",align="center"]

The user can determine which of the four panels are displayed by selecting the
*View* option on the main menu. This option gives the user several choices of
display:

*All*: show all four of the panels as in the screenshot above.

*Divelist*: Show only the Dive List.

*Profile*: Show only the Dive Profile of the selected dive.

*Info*: Show only the Dive Notes about the last selected dive and statistics for
all highlighted dives.

*Globe*: Show only the world map, centred on the last selected dive.

Like many other functions that can be accessed via the Main Menu, these options
can be triggered using keyboard shortcuts as well. The shortcuts for a
particular system
are shown with an underline in the menu entries. Since different Operating
Systems and the user chosen language may cause _Subsurface_ to use different
shortcut keys they will not be listed here in the user manual.

When the program is started for the first time, it shows no information at all.
This is because the program doesn't have any dive information available. In the
following sections, the procedures to create a new logbook will be described.

[[S_NewLogbook]]
Creating a new logbook
----------------------
Select _File -> New Logbook_ from the main menu. All existing dive data are
cleared so that new information can be added. If there is unsaved data in an
open logbook, _Subsurface_ the user will be asked if the open logbook will be
saved before a new logbook is created.

[[S_GetInformation]]
== How to obtain dive information to store in the user's logbook

There are several ways in which dive information can be added to a logbook:

1. Enter dive information by hand. This is typically useful if the diver did not
use a dive computer and dives were recorded in a written logbook.

2. Import dive information directly from a dive computer if it is supported by
_Subsurface_. The latest list of dive computers supported by _Subsurface_ can
be found at:
link:http://subsurface.hohndel.org/documentation/supported-dive-computers/[
Supported dive computers].

3. Import dive information from another data base or file format. This is
discussed in more detail below.

[[S_EnterData]]
=== Entering dive information by hand

This is usually the approach for dives without a dive computer. The basic record
of information within _Subsurface_ is a dive. The most important information
in a simple dive logbook usually includes dive type, date, time, duration,
depth, the names of your dive buddy and of the dive master or dive guide, and
some remarks about the dive. _Subsurface_ can store much more information
than this for each dive. In order to add a dive to a dive log, select _Log
-> Add Dive_ from the Main Menu. The program then shows three panels to enter
information for a dive: two tabs in the *Info* panel (*Dive Notes* and
*Equipment*), as well as the *profile* panel that displays a graphical profile
of each dive. These panels are respectively marked [red]#A#, [red]#B# and
[red]#C#
in the figure below. Each of these tabs will now be explained for data entry.

image::images/AddDive1.jpg["FIGURE: Add dive",align="center"]

==== Dive Notes

This panel contains the date, time and place information for a particular dive,
environmental conditions, co-divers and buddies, as well as some descriptive
information. The message in a blue box at the top of the panel indicates that
the dive is being edited. If one clicks on the *Dive Notes* tab, the following
fields are visible:

image::images/AddDive2.jpg["FIGURE: The Dive Notes tab",align="center"]

The *Starttime* field reflects the date and the time of the dive. By clicking
the down-arrow on the right of that field a calendar will be displayed from
which
one can choose the correct date. The time values (hour and minutes) can also be
edited directly by clicking on each of them in the text box and by overtyping the
information displayed.

*Air and water temperatures*: the air and water temperatures during the
dive can be typed directly on the fields to the right of the Starttime.
Temperature units are not needed, as they will be automatically supplied by
_Subsurface_. Only the numerical value must be
typed by the user (The units selected in the 'Preferences'
will determine whether metric or imperial units are used).

*Location*: Here the name of the dive site can be entered, e.g. "Tihany, Lake
Balaton,
Hungary". Auto completion of location names will make this easier if one
frequently dives at the same sites.

*Coordinates*: The geographic coordinates of the dive site should be entered
here. These can come from three sources:

a. One can find the coordinates on the world map in the bottom right hand
part
of the Subsurface window. The map displays a green bar indicating "No location
data - Move the map double-click to set the location". Upon a double-click
at the appropriate place, the green bar disappears and the coordinates are
stored.

b. The coordinates can be obtained from the _Subsurface_ Companion app if the
user has an Android device with GPS and if the coordinates of the dive site
were stored using that device.
xref:S_Companion[Click here for more information]

c. The coordinates can be entered by hand if they are known, using one of
four formats with latitude followed by longitude:

	ISO 6709 Annex D format e.g. 30°13'28.9"N 30°49'1.5"E
	Degrees and decimal minutes, e.g. N30° 13.49760' , E30° 49.30788'
	Degrees minutes seconds, e.g. N30° 13' 29.8" , E30° 49' 1.5"
	Decimal degrees, e.g. 30.22496 , 30.821798

Southern hemisphere latitudes are given with a *S*, e.g. S30°, or with a
negative value, e.g. -30.22496. Similarly western longitudes are given with a
*W*, e.g. W07°, or with a negative value, e.g. -7.34323.


*Divemaster*: The name of the dive master or dive guide for this dive can be
entered here.
Again, this field offers auto completion based on the list of dive masters in
the current logbook.

*Buddy*: In this field one can enter the name(s) of the buddy / buddies
(separated by commas) who accompanied the user on the dive. Auto completion
based on the list of buddies in the current logbook is offered.

*Suit*: The type of diving suit that was used for the dive can be entered here.
Just as with the
other items, auto completion of the suit description is available.

*Rating*: In this field, users can provide a subjective overall rating of the
dive on a 5-point scale by clicking the appropriate star on the rating scale.

*Visibility*: As with the previous item, users can provide a rating of
visibility during the dive on a 5-point scale by clicking the appropriate star.

*Tags*: Tags that describe the type of dive performed may
be entered here (separated by commas). Examples of common tags are boat, drift,
training, cave etc. _Subsurface_ has many built-in tags. Auto completion is once again offered.
For instance, if, for instance, +cav+ was typed, then the tags *cave* and *cavern* are
shown for the user to choose from.

*Notes*: Any additional information can be typed here.

The *Save* and *Cancel* buttons are used to save all the information for tabs in
the info panel and in the dive profile panel, so there's no need to use them
until ALL other information has been added. Here is an example of a completed
Dive Notes panel:

image::images/CompletedDiveInfo.jpg["FIGURE: A completed Dive Notes tab",align="center"]

==== Equipment

The Equipment tab allows the user to enter information about the type of
cylinder and gas used, as well as the weights used for a dive. The message in a
blue
box at the top of the panel:

image::images/BlueEditBar.jpg["Blue edit bar",align="center"]

indicates that the dive is being edited. This is a highly interactive part of
_Subsurface_ and the information on
cylinders and gases (entered here) affects the behaviour of the dive profile
(top right-hand panel).

*Cylinders*: The cylinder information is entered through a dialogue that looks
like this:

image::images/CylinderDataEntry1.jpg["FIGURE:Initial cylinder dialogue",align="center"]

The + button at the top right allows the user to add more cylinders for this
dive.
The dark dustbin icon on the left allows one to delete information for a
particular cylinder.

The user starts by selecting a cylinder type on the left-hand side of the
table.  To select a cylinder, the user must click in the *cylinder type* box.
This brings up a list button that can be used to display a dropdown list of
cylinders:

image::images/CylinderDataEntry2.jpg["FIGURE:The cylinder drop-down list button",align="center"]

This drop-down list can then be used to select the cylinder type that was used
for this dive. The
*Size* of the cylinder as well as its working pressure (*WorkPress*) will
automatically be shown in the dialogue.

Next, the user must indicate the starting pressure and the ending pressure of
the
gas used during the dive. The unit of pressure (metric/imperial) corresponds
to the setting in the preferences.

Finally, the user should type in the gas mixture used. If air
was used, a value of 21% can be entered on this field,  or the field might be
left blank. If nitrox or trimix were used, their percentages of oxygen and/or
helium must be specified.
Any inappropriate fields should be left empty. After typing the information for
the cylinder, press _ENTER_ on the keyboard or click
outside the cell that contains the cursor. Information for any additional
cylinders can be added by using the + button at the top right hand. Following
is an example of a complete description for a
dive made using two cylinders (air and EAN50):

image::images/CylinderDataEntry3.jpg["FIGURE: a completed cylinder dive information table",align="center"]

*Weights*: Information about the weight system used during a dive can be entered
using a dialogue very similar to that of the cylinder information. If the user
clicks the + button on the top right of the weights dialogue, the table looks
like this:

image::images/WeightsDataEntry1.jpg["FIGURE: The Weights dialogue",align="center"]

If one then clicks on the *Type* field, a drop-down list becomes accessible
through a down-arrow:

image::images/WeightsDataEntry2.jpg["FIGURE: Weights type drop-down list button",align="center"]

This drop-down list can then be used to select the type of weight system. In
the *Weight*
field, the weight used during the dive must be typed. After typing the
information
for the weight system the user must either press _ENTER_ on the keyboard or
click outside the
cell that contains the cursor. It is possible to enter
information for more than one weight system by adding an additional system using
the + button on the top right hand. Weight systems can be deleted using the
dustbin icon on the left hand. Here is an example of information for a dive
with two types of weights: integrated and a weight belt:

image::images/WeightsDataEntry3.jpg["FIGURE: A completed weights information table",align="center"]

There's NO need to click the _Save_ button before the dive
profile has beeb completed.

==== Creating a Dive Profile

The *Dive Profile* (a graphical representation of the depth of the dive as a
function of time) is indicated in the panel on the top right hand of the
_Subsurface_ window. When a dive is manually added to a logbook, _Subsurface_
presents a default dive profile that needs to be modified to best represent the
dive being described:

image::images/DiveProfile1.jpg["FIGURE: Initial dive profile",align="center"]

_Modifying the dive profile_: When the cursor is moved around the dive profile,
its position is indicated by two red lines as shown below. The depth and time
that the cursor represents are indicated, respectively on the left hand and
bottom axes. The units (metric/imperial) on the axes are determined by the
*preference* settings. The dive profile itself comprises several
line segments demarcated by waypoints (white dots on the profile, as shown
above). The default dive depth is 15 m.
If the dive depth was 21 m then the user needs to drag the appropriate waypoints
downwards to represent 21 m. To add a waypoint, double-click on
any line segment.
To remove a waypoint, right-click on it and choose "Remove this point" from the
context menu. The user will also need to drag the waypoints to represent an
accurate
time duration for the dive. Below is a dive profile that represents a dive
to 21 m for 31 min, followed by a 3 minute safety stop at 5 m.

image::images/DiveProfile2.jpg["FIGURE: Edited dive profile",align="center"]

_Specifying the gas composition:_ The gas composition used is clearly indicated
along the line segments of the dive profile. This defaults to the first gas
mixture specified in the *Equipment* tab, which was air in the case of the
profile illustrated above. The gas mixtures of segments of the dive profile can
be edited. This is done by clicking on the particular
waypoint and selecting the appropriate gas from the context menu. Changing
the gas for a waypoint affects the gas shown in the segment _to the left_ of
that
waypoint. Note that only the gases defined in the *Equipment* tab appear in the
context menu:

image::images/DiveProfile3.jpg["FIGURE: Gas composition context menu",align="center"]

Below is the profile of a dive to 21 m for 31 min with a switch from air to
EAN40 on the ascent. In this case the first cylinder in the *Equipment* tab
contained air and the second cylinder contained EAN40.

image::images/DiveProfile4.jpg["FIGURE: Completed dive profile",align="center"]

==== Saving the hand-entered dive information

The information entered in the *Dive Notes* tab, the *Equipment* tab as well as
the *Dive Profile* can now be saved in the user's logbook by using the two
buttons
on the top right hand of the Dive Notes tab. If the _Save_ button is clicked,
the dive data
are saved in the current logbook. If the _Cancel_ button is clicked, the newly
entered
dive data are discarded. When exiting _Subsurface_ the user will be prompted
once more to save the logbook with the new dive(s).


[[S_ImportDiveComputer]]
=== Importing new dive information from a Dive Computer

==== Connecting and importing data from a dive computer.

The use of dive computers allows the collection of a large amount of
information about
each dive, e.g. a detailed record of depth, duration, rates of ascent/descent
and of gas partial pressures. _Subsurface_ can capture this information and
present it as part of the dive information, using dive
information from a wide range of dive computers. The latest list of supported
dive computers can be found at:
link:http://subsurface.hohndel.org/documentation/supported-dive-computers/[
Supported dive computers].

[icon="images/icons/warning2.png"]
[WARNING]
Several dive computers consume more power when they are in their
PC-Communication mode. **This could drain the dive computer's battery**. We
therefore
recommend that the user checks if the dive computer is charged when
connected to the USB port of a PC. For example, several Suunto and Mares dive
computers do not recharge through the USB connection. The users should refer to
the dive computer's manual
if they are unsure whether the dive computer will recharge or drain its batteries
while connected to the USB port.

To import dive information from a dive computer to a computer with
_Subsurface_,
it is necessary that the two pieces of equipment communicate with one another.
This
involves setting up the communications port (or mount point) of the computer
with _Subsurface_ that communicates with the dive computer. In order to set up
this communication, one needs to find the appropriate information to
instruct
_Subsurface_ where and how to import the dive information. *Appendix A* provides
the technical information to help the user achieving this for different
operating
systems and *Appendix B* has dive computer specific information.

After this, the dive computer can be hooked up to the user's PC, which can be
achieved by following these steps:

 - The interface cable should be connected to a free USB port (or the Infrared
	or Bluetooth connection set up as described later in this manual)

 - The dive computer should be placed into PC Communication mode.
	(Users should refer to the manual of their specific dive computer)

 - In _Subsurface_, from the Main Menu, the user must select _Import -> Import
From Dive Computer_.
Dialogue *A* in the figure below appears:


image::images/ImportFromDC1.jpg["FIGURE: Download dialogue 1",align="center"]

Dive computers tend to keep a certain number of dives in their memory, even
though these dives have already been imported to _Subsurface_. For that reason
_Subsurface_ only imports dives that have not been uploaded before. This makes
the download process faster on most dive computers and also saves battery power
of the dive computer (at least for those not charging while connected via USB).
If, for some reason, the user wishes to import ALL dives from the dive computer,
even though some may already be in the logbook, then the the check box labeled
_Force download of all dives_ can be ticked.

 - The dialogue has two drop-down lists, *Vendor* and *Dive Computer*. On the
*vendor* drop-down list the user must select the make of the computer, e.g.
Suunto, Oceanic,
Uwatec, Mares. On the *Dive Computer* drop-down list, the model name of
the dive computer must be selected, e.g. D4 (Suunto), Veo200 (Oceanic), or Puck
(Mares).

 - The *Device or Mount Point* drop-down list contains the USB or Bluetooth port
name that _Subsurface_ needs in order to communicate with the dive computer.
The appropriate port name must be selected. Consult *Appendix A*
and *Appendix B* for
technical details on how to find the appropriate port information for a
particular dive
computer and, in some cases, how to do the correct settings to the operating
system of the computer on which _Subsurface_ is running.

 -  The _OK_ button must then be clicked. Dialogue *B* in the figure above
appears.

 - With communication established, one can see how the data is
retrieved from the
dive computer.
Depending on the make of the dive computer and/or number of recorded dives, this
could take some time. The user should be patient. The _Download_ dialogue
shows a
progress bar at the bottom of the dialogue (for some dive computers the
progress information could be inaccurate as we cannot determine how much
downloadable data there is until all data have been downloaded). When the
download of the dive information is complete, all the imported dives appear
in the Dive List, sorted by date and time. One can then disconnect and
switch off the dive
computer to conserve its battery power.
If a particular dive is selected, the Dive Profile panel shows an informative
graph of dive depth against time for that particular dive.


 - If there is a problem in communicating with the dive computer, an error
message will be shown, similar to this text: "Unable to open /dev/ttyUSB0 Mares
(Puck Pro)". Refer to the text in the box below.


****
[icon="images/icons/important.png"]
[IMPORTANT]
Check the following: 1) Is the dive computer still in PC-communication or
Upload mode?
2) Is the battery of the dive computer fully charged? If not then the battery
must be charged or replaced.
3) Is the connecting cable faulty? Does the cable work perfectly using other
software? Has it worked before, or is this the first time the cable is being used?
4) Consult *Appendix A* and make sure that the correct Mount Point
was specified (see above).
5) On Unix-like operating systems, does the user have write permission to the
USB port? If not, users should consult appendix *A*.

If the _Subsurface_ computer does not recognise the USB adaptor by
showing an appropriate device name next to the Mount Point, then there is a
possibility that the cable or USB adaptor is faulty. A faulty cable is the most
common cause of communication failure between dive computer and _Subsurface_
computer. It is also possible that the _Subsurface_ computer is missing
 data, one should perform a download with the following
two check boxes checked in the download dialogue discussed above:

	Save libdivecomputer logfile
	Save libdivecomputer dumpfile

When checking each of these boxes, the user is prompted to select a folder to
save the file into. The default folder is the one in which the _Subsurface_
dive log is kept. *Important:* After downloading, no dives are shown in the
*Dive List* but two files are created in the folder selected above:

	subsurface.log
	subsurface.bin

These files should be send to the _Subsurface_ mail list:
_subsurface@hohndel.org_ with a
request for the files to be analysed. One should provide the dive computer
make and model
as well as contextual information about the dives recorded on the dive computer.
****


[[S_EditDiveInfo]]
==== Updating the dive information imported from the dive computer.

The information from the dive computer is not complete and more
details must be added in order to have a more complete record of the dives. To
do this,
the *Dive Notes* and the *Equipment* tabs on the top left hand of the
_Subsurface_ window should be used.

==== Dive Notes

The date and time of the dive, gas mixture and perhaps water temperature is
shown as obtained from the dive computer, but the user needs to add some
additional information by hand in order to have a more complete dive record.
The message in a blue box at
the top of the panel indicates that the dive is being edited. If the user
clicks on the *Dive Notes* tab, the following fields are
visible:

image::images/AddDive3.jpg["FIGURE: The Dive Notes tab",align="center"]

The *Starttime* field reflects the date and the time of the dive, as supplied by
the dive computer. It should therefore not be necessary to edit this, but one
could make changes by clicking the down-arrow on the right of that field to
display a calendar from which the correct date can be chosen. The hour and
minutes values can also be edited by clicking on each of them in the text box
and by overtyping the information displayed.

*Air/water temperatures*: Air and water temperatures during the dive are shown
in these fields to the right of the Starttime. Many dive computers supply water
temperature information and this field may therefore not require further
editing. If
editing is required, only a value is required. The units of temperature will be
automatically supplied by
_Subsurface_ (according to the 'Preferences', metric or imperial units will
be used).

*Location*: In this field one should type in text that describes the site
where the dive was performed, e.g. "Tihany, Lake Balaton, Hungary". the required drivers to interact with the download cable and connected dive
computer.

If all the above points are in order and there is a failure to download the
dive
Auto completion of location names will
make this easier when a user frequently dives at the same sites.

*Coordinates*: The geographic coordinates of the dive site should be entered
here. These can come from three sources:

a. The user can find the coordinates on the world map in the bottom right hand
part
of the Subsurface window. The map displays a green bar indicating "No location
data - move the map and double-click to set the location". Double-click
at the appropriate place, the green bar disappears and the coordinates are
stored.

b. The user can obtain the coordinates from the _Subsurface_ Companion app if
an Android device with GPS was used and the if the coordinates of the dive site
were stored using that device.
xref:S_Companion[Click here for more information]

c. The coordinates can be entered by hand if they are known, using one of
three formats with latitude followed by longitude:

	ISO 6709 Annex D format e.g. 30°13'28.9"N 30°49'1.5"E
	Degrees and decimal minutes, e.g. N30° 13.49760' , E30° 49.30788'
	Degrees minutes seconds, e.g. N30° 13' 29.8" , E30° 49' 1.5"
	Decimal degrees, e.g. 30.22496 , 30.821798

Southern hemisphere latitudes are given with a *S*, e.g. S30°, or with a
negative value, e.g. -30.22496. Similarly western longitudes are given with a
*W*, e.g. W07°, or with a negative value, e.g. -7.34323.

*Divemaster*: The name of the dive master or dive guide for this dive should be
entered in this field.
This field offers auto completion based on the list of dive masters in
the current logbook.

*Buddy*: In this field, one enters the name(s) of the buddy / buddies
(separated with commas) who accompanied him/her on the
dive. Auto completion based on the list of buddies in the current logbook is
offered.

*Suit*: Here the type of diving suit used for the dive can be entered.
Auto completion of the suit description is available.

*Rating*: One can provide a subjective overall rating of the dive on a
5-point scale by clicking the appropriate star on the rating scale.

*Visibility*: Similarly, one can provide a rating of visibility during the
dive on a
5-point scale by clicking the appropriate star.

*Tags*: Tags that describe the type of dive performed can be entered
here (separated by commas). Examples of common tags are boat, drift, training,
cave, etc.
_Subsurface_ has many built-in tags. If the user starts typing a tag, the
program
will list the tags that correspond to the typing. For instance, if the user
typed
+cav+, then the tags *cave* and *cavern* are shown for the user to choose from.

*Notes*: Any additional information for the dive can be entered here.

The *Save* and *Cancel* buttons are used to save all the information for tabs
in the info panel and in the dive profile panel, so there's no need to use them
until ALL other information has been added. Here is an example of a completed
Dive Notes panel:

image::images/CompletedDiveInfo.jpg["FIGURE: A completed Dive Notes tab",align="center"]

==== Equipment

The Equipment tab allows one to enter information about the type of
cylinder and gas used as well as the weights used for the dive. The
message in a blue box at the top of the panel:

image::images/BlueEditBar.jpg["FIGURE: Blue edit bar",align="center"]

indicates that the dive is being edited.This is a highly interactive part of
_Subsurface_ and the information on
cylinders and gases (entered here) determines the behaviour of the dive profile
(top right-hand panel).

*Cylinders*: The cylinder information is entered through a dialogue that looks
like this:

image::images/CylinderDataEntry1.jpg["FIGURE: Initial cylinder dialogue",align="center"]

In most cases _Subsurface_ obtains the gas used from the dive computer and
automatically inserts the gas composition(% oxygen) in the table. The + button
at the top right allows the user to add more cylinders for this dive. The dark
dustbin icon on the left allows the deletion of information for a cylinder.

The user should start by selecting a cylinder type on the left-hand side of the
table.  To select a cylinder, the *cylinder type* box should be clicked. This
brings up a list button that can be used to display a dropdown list of
cylinders:

image::images/CylinderDataEntry2.jpg["FIGURE: The cylinder drop-down list button",align="center"]

The drop-down list can then be used to select the cylinder type that was used
for this dive. The
*Size* of the cylinder as well as its working pressure (*WorkPress*) will
automatically be shown in the dialogue.

Next one must indicate the starting pressure and the ending pressure of the
specified gas during the dive. The unit of pressure (metric/imperial)
corresponds to the settings chosen in the preferences.

Finally, the user must type in the gas mixture used. If air was used, the
value of 21%  can be entered here or this field can be left blank. If nitrox or
trimix were used, their percentages of oxygen and/or helium should be entered.
Any inappropriate fields should be left empty. After typing the
information for the cylinder,
either press _ENTER_ on the keyboard or click outside the cell
that contains
the cursor. Information for any additional cylinders can be added by using the +
button at the top right hand. Following is an example of a complete description
for a dive using two cylinders (air and EAN40):

image::images/CylinderDataEntry3.jpg["FIGURE: a completed cylinder dive information table",align="center"]

*Weights*: Information about the weight system used can be entered
using a dialogue very similar to that of the cylinder information. If one
clicks
the + button on the top right of the weights dialogue, the table looks like
this:

image::images/WeightsDataEntry1.jpg["FIGURE:The Weights dialogue",align="center"]

By clicking on the *Type* field, a drop-down list becomes accessible through a
down-arrow:

image::images/WeightsDataEntry2.jpg["FIGURE:Weights type drop-down list button",align="center"]

The drop-down list can then be used to select the type of weight system
used during the dive. In the *Weight*
field, type in the amount of weight used during the dive. After
specifying the weight
system, the user can either press _ENTER_ on the keyboard or click outside the
cell with the cursor.
It is possible to enter information for more than one weight system by adding
an additional system
using the + button on the top right hand. Weight systems can be deleted using
the dustbin icon on the left hand. Here is an example of information for a dive
with two types of weights: integrated and a weight belt:

image::images/WeightsDataEntry3.jpg["FIGURE: A completed weights information table",align="center"]

==== Saving the updated dive information

The information entered in the *Dive Notes* tab and the *Equipment* tab can be
saved with all the other information of the dives in the user's logbook by
using the
two buttons on the top right hand of the *Dive Notes* tab. If the _Save_ button
is clicked,
the dive data are saved. If the _Cancel_ button is clicked, then the newly
entered dive data are
deleted, although the dive profile obtained from the dive computer will be
retained. When the user exits _Subsurface_ there is a final prompt to confirm
that the new data should be saved.

=== Importing dive information from other digital data sources or other data
formats

[[S_ImportingAlienDiveLogs]]

If a user has been diving for some time, it's possible that several dives were
logged using other dive log software. All this information needs not
be typed by hand into _Subsurface_, because these divelogs can probably be
imported onto _Subsurface_. _Subsurface_ will import divelogs from a range of
other
dive log software. While some software is supported natively, for others the
user will have to
export the logbook(s) to an intermediate format so that they can then be imported
by _Subsurface_.
Currently, _Subsurface_ supports importing CSV log files from several sources.
APD LogViewer, XP5 and Sensus files are
preconfigured, but because the import is flexible, users can configure their own
imports.
Manually kept log files (e.g. in spreadsheet) can also be imported by
configuring the CSV import.
_Subsurface_ can also import UDDF and UDCF files that are used by some divelog
software and some divecomputers, like the Heinrichs & Weikamp DR5. Finally,
for some divelog software like Mares Dive Organiser it is currently suggested to
import the logbooks first into a webservice like _divelogs.de_ and then import
them from there with
_Subsurface_, as divelogs.de supports a few additional logbook formats that
_Subsurface_ currently cannot parse.

When importing dives, _Subsurface_ tries to detect multiple records for
the same dive and merges the information as best as it can. If
there are no time zone issues (or other reasons that would cause the
beginning time of the dives to be significantly different) _Subsurface_
will not create duplicate entries.

==== Using the universal import dialogue
[[Unified_import]]

Importing dives from other software is performed through a universal interface
that is activated by selecting _Import_ from the Main Menu, then clicking on
_Import Log Files_. This brings up the dialogue *A* below.

image::images/Import1.jpg["FIGURE: Import dialogue: step 1",align="center"]

Towards the bottom right is a dropdown selector with a default label
of _Dive Log Files_ which gives access to the different types of direct imports
available, as in dialogue *B*, above. Currently these are:

 - XML-formatted dive logs
 - UDDF-formatted dive logs
 - UDCF-formatted dive logs
 - JDiveLog
 - Suunto Dive Manager (DM3 and DM4)
 - MacDive (XML)
 - DivingLog 5.0 (XML)
 - Kenozooid (UDDF)
 - CSV (text-based and spreadsheet-based) dive logs.

Selecting the appropriate file in the file list of the dialogue opens
the imported dive log in the _Subsurface_ *Dive List*. A few other formats, not
accessible through the Import dialogue are also supported, as explained below.

==== Importing from Mares Dive Organiser V2.1

Since Mares utilise proprietory Microsoft software not compatible with
multi-platform software, these dive logs cannot be directly imported into
_Subsurface_. Mares dive logs need to be imported using a three-step process,
using _www.divelogs.de_ as a mechanism to extract the dive information from
the file.

 - The dive log data from Mares Dive Organiser need to be exported to the users
desktop, using
 a _.sdf_ file name extension. Users should refer to xref:Mares_Export[Appendix
C] for more information.
 - Data should then be imported into _www.divelogs.de_. One needs to create a user
account in
_www.divelogs.de_, log into that web site, then
select _Import Logbook -> Dive Organiser_ from the menu on the left hand side.
The instructions must be carefully followed to transfer the dive information
(in _.sdf_ format) from the Dive Organiser data base to _www.divelogs.de_.
 - Finally, the instructions below should be followed in order to import dives
from _divelogs.de_ to _Subsurface_.


[[S_ImportingDivelogsDe]]
==== Importing dives from *divelogs.de*

The import of dive information from _divelogs.de_ is simple, using a single
dialogue box. The _Import->Import form Divelogs.de_ option should be selected
from the Main Menu. This
brings up a dialogue box (see figure on left [*A*] below). one then needs to enter a
user-ID and password for _divelogs.de_ into the appropriate fields and then
select
the _Download_ button. Download from _divelogs.de_ starts immediately,
displaying a progress bar in the dialogue box. At the and of the download, the
succes status is indicated (see figure on the right [*B*], below). The
_Apply_ button should then be selected. The imported dives appear in the
_Subsurface_ *Dive List* panel.

image::images/Divelogs1.jpg["FIGURE:Download from Divelogs.de",align="center"]


[[S_ImportingCSV]]
==== Importing dives in CSV format

Sometimes dive computers export dive information as files with
_comma-separated values_ (.CSV). For example, the APD Inspiration and Evolution
closed circuit rebreather (CCR) systems export dive information in CSV format
that normally contains information about a single dive only. These
files can easily be imported into _Subsurface_.
CSV files are normally organised into
a single line that provides the headers of the data columns, followed by the
data, one record per line. CSV files can be opened with a normal text editor.
Following is a highly simplified and shortened example of a CSV file from an
APD rebreather:

	Dive Time (s)	Depth (m)	PPO2 - Setpoint (Bar)	PPO2 - C1 Cell
1 (Bar)	Ambient temp. (Celsius)
	0	0.0	0.70	0.81	13.1
	0	1.2	0.70	0.71	13.1
	0	0.0	0.70	0.71	13.1
	0	1.2	0.70	0.71	13.2
	0	1.2	0.70	0.71	13.1
	10	1.6	0.70	0.72	12.7
	20	1.6	0.70	0.71	12.6
	30	1.7	0.70	0.71	12.6
	40	1.8	0.70	0.68	12.5
	50	1.6	0.70	0.68	12.5
	60	2.4	0.70	0.69	12.5
	70	3.5	0.70	0.69	12.4
	80	4.2	0.70	0.72	12.5
	90	4.0	0.70	0.71	12.4

Note that each title may comprise more than one word; for instance
'Dive Time (s)' in the above data example. Before being able to import the data
to _Subsurface_ one first needs to know:

a. Which character separates the different columns within a single line of
data? This field separator should be either a comma (,) or a TAB character.
This can be determined by opening the file with a text editor. If it is
comma-delimited, then the comma
characters between the values are clearly visible. If no commas are evident and
the numbers are aligned,
the file is probably TAB-delimited (i.e. it uses a TAB as a field separator, as
in the above example).

b. Which data columns need to be imported into _Subsurface_?. The Dive Time and
Depth columns are always required. Open the file using a text editor and note
the titles of the columns to be imported and their column positions. For
instance for the above example:

	Time:		column 1
	Depth:		column 2
	Temperature:	column 5
	ppO2:		column 4

Armed with this information, importing it into _Subsurface_ is a
straightforward process. User should select
_Import->Import Log Files_ from the main menu. In the appearing file
selection menu, users need to select one or more CSV files. Its format is
detected by the file
extension, and a common configuration dialog is presented for all the
files with a CSV extension. The configuration dialog is like the following:

image::images/Import_CSV1.jpg["FIGURE: CSV download dialogue",align="center"]

Then the user must specify the name of the CSV file or select it from the
browser button on the right.
There are pre-configured definitions for some dive computers, e.g. the APD
rebreathers. If the user's dive computer is on this list, it should be selected
using the dropdown
box labeled _Pre-configured imports_. Finally the _OK_ should be clicked and
the dive will be imported and listed in the *Dive List* tab of _Subsurface_.

If the dive computer is not on the pre-configured list, the user must
select the _Field
Separator_ (TAB or comma) for the particular CSV file, using the appropriate
dropdown list. and indicate which columns in the CSV file
contain which data
variables. For each data column used for import, the user must check the
appropriate check box
and indicate in which column these data are found. For instance, the image above
corresponds to the dialogue that would apply to the CSV data set described above
the image. Having performed the column specification, select the _OK_ button
and the dive will be imported and listed in the *Dive List* tab of _Subsurface_.


[[S_ImportingManualCSV]]
==== Importing dives from manually kept CSV file

If one keeps dive logs in a spreadsheet, there is an option to import
those dives as well. Spreadsheet data, exported as a CSV file, can
be imported to _Subsurface_. When importing manually
kept log files, the information needed is quite different as we are
importing only metadata, not profile samples.

Similarly to importing dives in CSV format (see above), one needs to
know the internal format
of the CSV data to import.

a. Which character separates the different columns within a single line of
data? This
should be either a comma (,), semicolon (;) or a TAB
character, and could be determined by opening the file with a text
editor. If it is comma-delimited, then the comma
characters between the values are clearly visible. If no commas are evident and
the data
are in clear columns, the file
is probably TAB-delimited (i.e. it uses a TAB as a field separator, as in the
above example).
A recommended field separator for the export is tab, as commas might be used in
the
field values themselves.

b. Which columns need to be imported into _Subsurface_?. We do not
currently have any mandatory input fields, but some, e.g. dive duration
are crucial for the log file to make any sense. Possible options
can be seen in the image below and one should include all the
fields available in both your log file and in the Subsurface
import.

c. Units used for depth, weight and temperature. We consider depth to be
either feet or meters, weight kilograms or pounds and temperature either
Celsius or Fahrenheit. However, the users can only select _Metric_ or
_Imperial_ in the Preferences tab of _Subsurface_.. No mixture of unit s
ystems is allowed for the different fields.

Importing manually kept CSV log files is quite straight forward, but
there might be many fields and counting the field numbers is error
prone. Therefore validation of the data to be imported is critical.

To import the dives, one must select _Import->Import Log Files_ from the menu
bar. If the CSV option in the dropdown list is selected and the file list
includes file names ending with .CSV, one can select the
_Manual dives_ tab that will bring up the following configuration dialog:

image::images/Import_CSV2.jpg["FIGURE: Download dialog for Manual CSV logs",align="center"]

The input fields can be configured as appropriate, and when everything is done
the _OK_ button should be selected to perform the import. New dives should
appear in the *Dive List* area of _Subsurface_.


[[S_Companion]]
=== Importing GPS coordinates with the Subsurface Companion app for mobile
phones
If the user has an Android device with GPS, the coordinates for the diving
location can be obtained and automatically passed to Subsurface
divelog. To do this, one needs to:

- Register on the http://api.hohndel.org/login/[Subsurface companion web page].
A confirmation mail with instructions and a personal *DIVERID* will be send together with
a long number that gives access to the companion app capabilities.

- Download the app from
https://play.google.com/store/apps/details?id=org.subsurface[Google Play Store]
or
from
http://f-droid.org/repository/browse/?fdfilter=subsurface&fdid=org.subsurface[F-Droid].

==== Using the Subsurface companion app on a smartphone

On first use the app has three options:

* _Create a new account._  Equivalent to registering in _Subsurface_ companion
page.

* _Retrieve an account._  If users forgot their DIVERID they will receive an email
to recover the number.

* _Use an existing account._ Users are prompted for their DIVERID. The app saves
this DIVERID and does not ask for it again unless one uses the _Disconnect_ menu
option (see below).

Now one is ready to get a dive position and send it to the server. The Android
display will look like the left hand image (A) below, but without any dive.

Touching the "+" icon on the top right to add a new dive site. Users will be
prompted for a place name (or asked to activate the GPS if it was turned off).
The main screen shows a list of dive locations, each with a name, date and
time. Some dives may have an arrow-up icon on the selection box to the left (see
image B in the middle, below) indicating that they require upload to the server.

There are several ways to send dives to the server; the easiest is by simply
selecting the dive. See middle image below (B):

image::images/Companion.jpg["FIGURE: Screen shots (A-C) of companion app",align="center"]

Touching the right arrow will send it to the server.

[icon="images/icons/important.png"]
[IMPORTANT]
Users must be careful, as the trash icon on the right means exactly what it is supposed to mean,
it deletes the dive location(s).

The new dive points are now stored on the server and can be downloaded to the
_Subsurface_ dive log whenever users upload or add dives to _Subsurface_.
After a dive trip using the Companion app, all dive locations are ready to be
saved on a Subsurface dive log (see below).

===== Settings on the Companion app

Selecting the _Settings_ menu option results in the right hand image above (C).

===== Server and account

- _Web-service URL._ This is predefined (http://api.hohndel.org/)

- _User ID._ Obtained by registering as indicated above. The easiest way to
obtain it is simply to copy and paste from the confirmation mail but, of
course, users can also type this information.

===== Synchronization

- _Synchronize on startup._ If selected, dives in the Android device and those
on the web service will synchronize each time the app is started.

- _Upload new dives._ If selected, each time the user adds a dive location it will
automatically be sent to the server.

===== Background service
Instead of entering a unique dive location, users can leave the service running
in the background of their device, thus allowing the continuous collection of GPS locations.


The settings below define the behaviour of the service:

- _Min duration._ In minutes. The app will try to get a position each X minutes
until it's stopped by the user.

- _Min distance._ In meters. Minimum distance between two position fixes.

- _Name template._ The name the app will use when saving the position fixes.

[icon="images/icons/info.jpg"]
[TIP]
_How does the background service work?_ Assuming that the user set 5 minutes and 50
meters in the settings above, the app will start by taking a fix at the current location,
followed by another one
at every 5 minutes. If this 2nd (3rd, 4th ...) location is within a radius of 50
meters from the previous one, then this new fix is not saved. If the user is not moving,
only one fix is saved, but if the user is moving, then a trace of the journey is obtained,
by saving each new position at every 5 minutes.

===== Other

- _Mailing List._ The mail box for _Subsurface_. Users can send an email to the
Subsurface mailing list.

- _Subsurface website._ A link to the URL of Subsurface web

- _Version._ Displays the current version of the companion app.

===== Search

Here one can search one's saved dive locations by the name or by date and hour.

===== Start service

Initiates the _background service_ depending on the previously defined settings.

===== Disconnect

This is a badly named option. It disconnects the app from the server by
resetting the user ID in the app, showing the first screen where an account
can be created, retrieve the ID for an existing account or use the users own
ID. The disconnect option
is useful if a user's Android device was used to download the dive positions
of another registered diver.

===== Send all locations

This option sends all locations stored in the Android device to the server.


==== Downloading dive locations to a Subsurface divelog

Download dive(s) from a dive computer or enter them manually into
_Subsurface_ before obtaining the GPS coordinates from the server. The download
dialog can be reached via _Ctrl+G_ or from the _Subsurface_ Main Menu _Import
-> Import GPS data from Subsurface Service_, resulting in the image on the
left (*A*), below. On first use the DIVERID text box will be blank. Users must provide their
DIVERID and then select the _Download_ button to initiate the download process. When this
is completed, users will see the screen on the right (*B*), below:

image::images/DownloadGPS.jpg["FIGURE: Downloading Companion app GPS data",align="center"]

Note that the _Apply_ button is now active. By clicking on it, users can update the locations
of the newly entered or uploaded dives in _Subsurface_ which applies the
coordinates and names entered on the app for all the new dives that match the
date-times of the uploaded GPS localities.

[icon="images/icons/info.jpg"]
[NOTE]
Features, issues and tips._  Since _Subsurface_ matches GPS locations from the
Android device and dive information from the dive computer based on date-time
data, automatic assignment of GPS data to dives is dependent on agreement of
date and time between these two devices. If there is a large difference between
the time in the dive computer and the time in the Android device,
_Subsurface_ is unable to identify the dive matching a location and nothing
happens. Similar date-times may be not always be possible.  A dirty hack is
manually editing the date-time of a dive in Subsurface's Dive List _before_
downloading the GPS data and then to edit the date-time back again _after_
downloading GPS data.

== Obtaining more information about dives entered into the logbook

=== The *Dive Info* tab (for individual dives)

The Dive Info tab gives some summary information about a particular dive that
has been selected in the *Dive List*. Useful information here includes the
surface interval before the dive, the maximum and mean depths of the dive, the
gas volume consumed, the surface air consumption (SAC) and the number of oxygen
toxicity units (OTU) incurred.

[icon="images/icons/info.jpg"]
[NOTE]
Gas consumption and SAC calculations:
_Subsurface_ calculates SAC and Gas consumption taking in account gas
incompressibility, particularly at tank pressures above 200 bar, making them more accurate.
Users should refer to xref:SAC_CALCULATION[Appendix D] for more information.

=== The *Stats* tab (for groups of dives)

The Stats tab gives summary statistics for more than one dive, assuming that
more than one dive have been selected in the *Dive List* using the standard
Ctrl-click or Shift-click of the mouse. If only one
dive has been selected, figures pertaining to only that dive are given. This tab
shows the number of dives selected, the total amount of dive time in these
dives,
as well as the minimum, maximum and mean for the dive duration, dive depth,
water temperature and surface air consumption (SAC).

[[S_DiveProfile]]
=== The *Dive Profile*

image::images/Profile2.png["Typical dive profile",align="center"]

Of all the panels in _Subsurface_, the Dive Profile contains the most detailed
information about each dive. The main item in the Dive profile is the graph of
dive depth as a function of time. In addition to the obvious information of
the depth it also shows the ascent and descent rates compared to the recommended
speed of going up or down in the water column. This information is given using
different colours:
|====================
|*Colour*|*Descent speed (m/min)*|*Ascent speed (m/min)*
|Red|> 30|> 18
|Orange|18 - 30|9 - 18
|Yellow|9 - 18|4 - 9
|Light green|1.5 - 9|1.5 - 4
|Dark green|< 1.5|< 1.5
|=====================

The profile also includes depth readings for the peaks and troughs in the graph.
Thus, users should see the depth of the deepest point and other peaks. Mean depth
is marked with a horizontal red line.

The *air consumption* graph displays the tank pressure and its change during the
dive. The air consumption takes depth into account so that even when manually
entering the start and end pressures the graph is not a straight line.
Similarly to the depth graph the slope of the tank pressure gives the user information
about the
momentary SAC rate (Surface Air Consumption) when using an air integrated dive computer.
Here the colour
coding is not relative to some absolute values but relative to the average
normalised air consumption during the dive. So areas that are red or orange
indicate
times of increased normalized air consumption while dark green reflects times
when the diver was using less gas than average. The colour coding is obviously
only possible when a tank sensor is connected and tank pressure readings during
the dive are available.

*Water temperature* is displayed with its own blue line with temperature values
placed adjacent to significant changes.

It is possible to *zoom* into the profile graph. This is done either by using
the scroll wheel / scroll gesture of your mouse or trackpad. By default
_Subsurface_ always shows a profile area large enough for at least 30 minutes
and 30m
 (100ft) – this way short or shallow dives are intuitively recognizable;
something
that free divers clearly won’t care about.

image::images/MeasuringBar.png["FIGURE: Measuring Bar",align="center"]

Measurements of *depth differences* can be achieved by using the button with
two vertical bars at the right of the dive profile panel (users should refer to
the above figure,
bottom right). The measurement is done by dragging the red dots to the two points
on the dive profile that the user wishes to measure. Information is then given
along the line connecting the
two red dots.

The dive profile can include further information that is typically more
interesting for tec divers. Enabling these is described in the section entitled
_Setting up Preferences_. Basically, users can include graphs of the *partial
pressures*
of O2, N2, and He during the dive as well as a calculated and dive computer
reported deco ceilings (only visible for deep, long, or repetitive dives). The
partial pressure graphs are added below the profile data, the calculated ceiling
is shown as a green overlay on top of the dive profile. Above the profile the
currently used gradient factors are shown (e.g. GF 35/75). Please note that
these are NOT the gradient factors in use by the dive computer in question,
but the gradient factors used by _Subsurface_ to calculate deco obligations
during the dive.

The graph can also include the dive computer reported *ceiling* (or more
precisely, the first deco stop that the dive computer recorded – users are reminded that not
all dive computers record this information and make it available for download;
for example all of the Suunto dive computers fail to make this very useful data
available to divelog software). Because of the differences in used algorithms
and amount of data available (and factors taken into consideration) at the time
of the calculation it is unlikely that both of these are the same; this can be
true even if the same algorithm and _gradient factors_ (see below) are used.
It is also quite common that _Subsurface_ calculates a ceiling for
non-decompression dives when the dive computer stayed in non-deco mode during
the whole dive (represented by the [green]#dark green# section in the profile
at the beginning of this section). This is caused by the fact that
_Subsurface’s_
calculations describe the deco obligation at that point in time during a dive,
while dive computers usually take the upcoming ascent into account. During the
ascent some excess Nitrogen (and possibly Helium) are already breathed off so
even
though the diver technically encountered a ceiling at depth, the dive still does
not require an explicit deco stop. This feature allows dive computers to offer
longer non-stop bottom time.

For a more detailed explanation of _gradient factors_, use the following links:

- link:http://www.tek-dive.com/portal/upload/M-Values.pdf[Understanding M-values, by Erik Baker, 1988, _Immersed_ Vol. 3, No. 3.]

- link:http://www.rebreatherworld.com/general-and-new-to-rebreather-articles/5037-gradient-factors-for-dummies.html[Gradient factors for dummies, by Kevin Watts]


=== The Dive Profile context menu

The context menu for the Dive Profile is accessed by right-clicking while the
mouse cursor is over the Dive Profile panel. The menu allows the creation of
Bookmarks or Gas Change Event markers other than the ones that might have been
imported from a Dive Computer. Markers are placed against the depth profile line
and with the time of the event set by where the mouse cursor was when the right
mouse button was initially clicked to bring up the menu. Gas Change events
open a further selection of which gas is being switched to, the list based on
the available gases defined in the Equipment Tab. By right-clicking while over
an existing marker, the menu extends adding options to allow deletion of the
marker or to allow all markers of that type to be hidden. Hidden events can be
restored to view by selecting Unhide all events from the context menu.

=== The *Information Box*

The Information box displays a large range of information pertaining to the dive
profile. Normally the Information Box is located to the top left of the *Dive
Profile* panel. If the mouse points outside of the *Dive Profile* panel, then
only the top line of the Information Box is visible (see left-hand part of
figure (A) below). The Information Box can be moved around in the *Dive Profile*
panel by click-dragging it with the mouse so that it is not obstructing
important detail. The position of the Information Box is saved and used again
during subsequent dive analyses.

image::images/InfoBox2.jpg["Figure: Information Box",align="center"]

The moment the mouse points inside the *Dive Profile* panel, it expands and
shows many data items. In this situation, the data reflect the time point along
the dive profile indicated by the mouse (see right-hand part of figure (B) above
where the Information Box reflects the situation at the position of the cursor
[arrow] in that image). Therefore, moving the cursor in the horizontal
direction allows the Information Box to show information for any point along the
dive profile.
In this mode, the Information Box gives extensive statistics about depth, gas
and ceiling characteristics of the particular dive. These include: Time period
into the dive (indicated by a @), depth, cylinder pressure (P), temperature,
ascent/descent rate, surface air consumption (SAC), oxygen partial pressure,
maximum operating depth, effective air depth (EAD), effective narcotic depth
(END), equivalent air density depth (EADD), decompression requirements at that
instant in time (Deco), time to surface (TTS), the calculated ceiling, as well
as the calculated ceiling for several Bühlmann tissue compartments.


== Organising the logbook (Manipulating groups of dives)

=== The Dive List context menu

Many actions within _Subsurface_ are dependent on a context menu used
mostly to manipulate  groups of dives. The context menu is found by selecting
a dive or a group of dives and then right-clicking.

image::images/ContextMenu.jpg["Figure: Context Menu",align="center"]

The context menu is used in many manipulations described below.

[[S_Renumber]]
=== Renumbering the dives

Dives are normally numbered incrementally from non-recent dives (low sequence
numbers) to recent dives (having the highest sequence numbers). The numbering
of the dives is not always consistent. For instance, when non-recent dives are
added to the dive list the numbering does not automatically follow on because
of the dives that are more recent in date/time than the newly-added dive that
has an older date/time. Therefore, one may sometimes need to renumber the dives.
This is performed by selecting (from the Main Menu) _Log -> Renumber_. Users are
given a choice with respect to the lowest sequence number to be used.
Completing this operation results in new sequence numbers (based on date/time)
for the dives in the *Dive List* panel.

[[S_Group]]
=== Grouping dives into trips and manipulating trips

For regular divers, the dive list can rapidly become very long. _Subsurface_
can group dives into _trips_. It performs this by grouping dives that have
date/times that are not separated in time by more than two days, thus creating
a single heading for each diving trip represented in the dive log. Below is an
ungrouped dive list (*A*, on the left) as well as the corresponding grouped dive
list comprising five dive trips (*B*, on the right):

image::images/Group2.jpg["Figure: Grouping dives",align="center"]

Grouping into trips allows a rapid way of accessing individual dives without
having to scan long lists of dives. In order to group the dives in a dive list,
(from the Main Menu) users must select _Log -> Autogroup_. The *Dive List* panel now shows
only the titles for the trips.

==== Viewing the dives during a particular trip
Once when the dives have been grouped into trips, users can expand one or more
trips by clicking the arrow-head on the left of each trip title. This expands
the selected trip, revealing the individual dives performed during the trip.

==== Editing the title and associated information for a particular trip

Normally, in the dive list, minimal information is included in the trip title.
More information about a trip can be added by selecting its trip title from
the dive list. This shows a *Trip Notes* tab in the *Dive Notes* panel. Here
users can add or edit information about the date/time, the trip location and any
other general comments about the trip as a whole (e.g. the dive company that was
dived with, the general weather during the trip, etc.). After entering this
information, users should select *Save* from the buttons at the top right of the *Trip Notes*
tab. The trip title in the *Dive List* panel should now reflect some of the
edited information.

==== Collapsing or expanding dive information for different trips

If a user right-clicks after selecting a particular trip in the dive list, the
resulting context menu allows several possibilities to expand or collapse dives
within trips. This includes expanding all trips, collapsing all trips and
collapsing all trips except the selected one.

==== Merging dives from more than one trip into a single trip

By right-clicking on a selected trip title in the *Dive List* panel, a
context menu shows up that allows the merging of trips by either merging of the selected trip
with the trip below or with the trip above.

==== Splitting a single trip into more than one trip

If a trip includes five dives, the user can split this trip into two trips (trip 1:
top 3 dives; trip 2: bottom 2 dives) by selecting and right-clicking the top
three dives. The resulting context menu allows the user to create a new trip by
choosing the option *Create new trip above*. The top three dives are then
grouped
into a separate trip. The figures bellow show the selection and context menu on the left (A) and
the completed action on the right (B):

image::images/SplitDive3a.jpg["FIGURE: Split a trip into 2 trips",align="center"]

=== Manipulating single dives

==== Delete a dive from the dive log

Dives can be permanently deleted from the dive log by selecting and
right-clicking them to bring up the context menu, and then selecting *Delete
dive(s)*. Typically this would apply to a case where a user wishes to delete
workshop
calibration dives of the dive computer or dives of extremely short duration.

==== Unlink a dive from a trip

Users can unlink dives from the trip to which they belong. In order to do this,
users should select and right-click
the relevant dives to bring up the context menu. Then the option *Remove dive(s)
from trip* should be selected.
The dives that have been unlinked now appear immediately above the trip to
which they belonged.

==== Add a dive to the trip immediately above

Selected dives can be moved from the trip to which they belong and placed within
the trip immediately above the currently active trip. To do this, users must select
and right-click
the dives to bring up the context menu, and then select *Add dive(s) to trip
immediately above*.

==== Shift the start time of dive(s)

Sometimes it is necessary to adjust the start time of a dive. This may apply to
situations where dives are performed in different time zones or when the dive
computer has an erroneous time. In order to do this, user must select and right-click
the dive(s) to be
adjusted. This action brings up the context menu on which the *Shift times*
option should be selected. User must then specify the
time
(in hours and minutes) by which the dives should be adjusted and click on the
option indicating whether the time adjustment should be forwards or backwards.

==== Merge dives into a single dive

Sometimes a dive is briefly interrupted, e.g. if a diver returns to the surface
for a few minutes, resulting in two or more dives being recorded by the dive
computer and appearing as different dives in the *Dive List* panel. Users can
merge these dives onto a single dive by selecting the appropriate dives,
right-clicking them to bring up the context menu and then selecting *Merge selected
dives*. It may be necessary to edit the dive information in the *Dive Notes*
panel to reflect events or conditions that apply to the merged dive. The figure
below shows the depth profile two such dives that were merged:

image::images/MergedDive.png["Example: Merged dive",align="center"]

[[S_ExportLog]]
== Exporting the dive log or parts of the dive log

A dive log can be saved in two formats:

* _Subsurface_ XML format. This is the native format used by _Subsurface_.

* Universal Dive Data format (UDDF). User should refer to http://uddf.org for more information.
UDDF is a generic format that enables communication among many dive computers
and computer programs.

In order to save the WHOLE dive log (i.e. all trips and dives), *File* should be selected
from the Main menu. To save in _Subsurface_ XML format, users should select _File -> Save
as_. To save in UDDF format, the _File -> Export UDDF_ option should be selected.

In order to save only one or more dives or one or two trips, users can select the
appropriate dives or trips in the *Dive List* panel and then right-click the
selected dives to bring up the context menu. To save in _Subsurface_ XML
format, users should select _Save as_ from the context menu. To save in UDDF format, users should select
_Export as UDDF_ from the context menu.


[[S_PrintDivelog]]
== Printing a dive log

_Subsurface_ provides a simple interface to print a whole dive log or only a
few selected dives, including dive profiles and other contextual information.

Before printing, two decisions are required:

- Should the whole dive log be printed or only part of it? If only part of the
dive log is required, then the user must select the required dives from the *Dive List* panel.
- What gas partial pressure information is required on the dive profile? Users should select
the appropriate information from the Main Menu: _File->Preferences->Graph_.

Now the print options should be selected to match the user's needs. To do this, user should select _File->Print_ from
the Main menu. The following dialogue appears (see the image on the left [A],
below).

Under _Print type_ users need to select one of three options:

- Print the Dive List: to do this, _Table Print_ should be selected.
- Print the full dive records (dive profiles and all other information) at 6
dives per printed page: to do this, users should select _6 dives per page_.
- Print the full dive records (dive profiles and all other information) at 2
dives per printed page: to do this, users should select _2 dives per page_.

Under _Print options_ users need to select:

- Printing only the dives that have been selected from the dive list prior to
activating the print dialogue, achieved by checking the box _Print only
selected dives_.
- Printing in colour, achieved by checking the box with _Print in color_.

The _Ordering_ affects the layout of the page (or part of it) for each dive.
The dive profile could be printed at the top of each dive, with the textual
information underneath, or it could be printed with the textual information at
the top with the dive profile underneath. Users should select the appropriate option in the
print dialogue. See the image on the right (*B*), above which has a layout with
text above the dive profile.

Users can _Preview_ the printed page by selecting the _Preview_ button on the
dialogue. After preview, changes to the options in the print dialogue can be
made, resulting in a layout that fits personal taste.

image::images/PrintDiveLog.jpg["FIGURE: Print dialogue",align="center"]

Next, select the _Print_ button in the dialogue. This activates the regular print
dialogue used by the user operating system (image [*B*] in the middle, above),
allowing them to choose a printer and to set its properties (image [*C*] on the right,
above).
It is important to set the print resolution of the printer to an appropriate value by
changing
the printer properties. Finally, users can print their dives. Below is a (rather small)
example of
the output for one particular page.

image::images/Printpreview.jpg["FIGURE: Print preview page",align="center"]


[[S_Preferences]]
== Setting user *Preferences* for _Subsurface_

There are several settings within _Subsurface_ that the users can specify. These
are found when selecting _File->Preferences_. The settings are performed in
four groups: *Defaults*, *Units*, *Graph* and *Language*. All four sections
operate on the same principles: the user must specify the settings the are to be changed, then
these changes are saved using the *Apply* button. After applying all the new settings users can then
leave the settings panel by selecting *OK*.

=== Defaults

There are four settings in the *Defaults* panel:

image::images/Preferences1.jpg["FIGURE: Preferences defaults page",align="center"]

  ** *Lists and tables*: Here one can specify the font type and font size of the
Dive Table panel. By decreasing the font size of the Dive table, users can see more dives on a screen.

  ** *Dives*: Here one need to specify the directory and file name of one's
electronic dive log book(s). This is a file with filename extension .xml. When
launched, _Subsurface_ will then automatically load the specified dive log book.

  ** *Display invalid*:  Dives can be marked as invalid (when a user wishes to hide
dives that he/she don't consider valid dives, e.g. pool dives, but still want to
keep them in the dive log). This controls whether those dives are displayed in
the dive list.

  ** *Use Default cylinder*: Here users can specify the default cylinder listed in
the *Equipment* tab of the *Dive Notes* panel.

=== Units
image::images/Preferences2.jpg["FIGURE: Preferences Units page",align="center"]

Here user can choose between metric and imperial units of depth, pressure,
volume, temperature and mass. By selecting the Metric or Imperial radio button
at the top, users can specify that all units are in the chosen measurement system.
Alternatively, if one selects the *Personalise* radio button, units can be selected
independently, with some units in the metric system and other in the imperial.

=== Graph
image::images/Preferences3.jpg["FIGURE: Preferences Graph page",align="center"]

This panel allows two type of selections:

* *Show*: Here users can specify the amount of information shown as part of
the dive profile:
** Gas pressure graphs: _Subsurface_ can display the nitrogen, oxygen and the helium partial pressures during
the dive. For each of these graphs users can specify a threshold value on the right-hand side of the
panel. If any of the graphs go above this threshold level, the graph is
highlighted in red, indication that the threshold value has been exceeded (see
figure below).

** Ceiling: Ascent ceilings arise when a direct ascent to the surface increases
the risk of a diver suffering from decompression sickness (DCS) and it is necessary to either ascend
slower or to perform decompression stop(s) before ascending to the surface.
_Subsurface_ can indicate these ceilings above which the diver should not ascend
at a particular point in time (see the green-shaded areas in the figure in the
section on <<S_DiveProfile,Dive Profiles>>) and in the figure below:

*** If the *Calculated ceiling* option is checked, then a ceiling is shown if it exists for
a particular dive (*A* in figure below)

*** If the *show all tissues* option is checked, the ceiling is shown for the tissue
compartments following the Bühlmann model (*B* in figure below).

*** If the *3m increments* option is checked, then the ceiling is indicated in 3 m increments
(*C* in figure below).

*** If the dive computer itself calculates a ceiling and makes it available to
_Subsurface_ during upload of dives, this can be
shown by checking *Dive computer reported ceiling* and it can be drawn in red by
checking *Draw ceiling red*.

** If a _Maximum operating depth (MOD)_ or an _Equivalent air depth (EAD)_
applies to a dive profile, these can be shown by checking the appropriate boxes.

** If a _Maximum partial pressure of oxygen (maxPPO2)_ applies to dives, then
this can be specified in the appropriate text box. In addition, if a
_no-decompression limit (NDL)_ is to be shown in the *info* box, then users must check the
appropriate box.

image::images/Ceilings.png["Figure: Ceiling with 3m resolution",align="center"]

* *Misc*: Here users can set the _gradient factors_ used while diving. GF_Low is
the gradient factor at deep and GF_High is used just below the surface.
At intermediate depths gradient factors between GF_Low and GF_High are used.
Gradient factors add conservatism to the nitrogen exposure during a dive, in a
similar way that many dive computers have a conservatism setting. The lower
the value of a gradient factor, the more conservative the calculations are with
respect to nitrogen loading and the deeper the ascent ceilings are. Gradient
factors of 25/60 are considered conservative and values of 60/90 are considered
harsh. Checking *GFLow at max depth* box causes GF_Low to be used at the
deepest depth of a dive. For more information see:

 ** http://www.tek-dive.com/portal/upload/M-Values.pdf[Understanding M-values by Erik Baker, , _Immersed_ Vol. 3, No. 3.]

 ** link:http://www.rebreatherworld.com/general-and-new-to-rebreather-articles/5037-gradient-factors-for-dummies.html[Gradient factors for dummies, by Kevin Watts]

=== Languages
A checkbox allows one to use the _System Default_ language which in most cases
will be the correct setting; with this _Subsurface_ simply runs in the same
language / country settings as the underlying OS. If this is for some reason
undesirable users can uncheck this checkbox and pick a language / country
combination from the list of included localizations.

== Description of the Subsurface Main Menu items

This section describes the functions and operation of the items in the Main Menu
of Subsurface. Several of the items below are links to sections of this manual
dealing with the appropriate operations.

=== File
- <<S_NewLogbook,_New Logbook_>> - Close the currently open dive logbook and
clear all dive information.
- _Open logbook_ - This opens the file manager in order to select a dive
logbook to open.
- _Save_ - Save the dive logbook that is currently open.
- _Save as_: - Save the current logbook or the currently selected dives within
the present logbook under a different filename.
- _Close_ -  Close the dive logbook that is currently open.
- <<S_ExportLog,_Export UDDF_>> -  Export the currently open dive logbook (or
the selected dives in the logbook) in UDDF format.
- <<S_PrintDivelog,_Print_>> -  Print the currently open logbook.
- <<S_Preferences,_Preferences_>> -  Set the _Subsurface_ preferences.
- _Quit_ - Quit _Subsurface_.

=== Import
- <<S_ImportDiveComputer,_Import from dive computer_>> - Import dive information
from a dive computer.
- <<Unified_import,_Import Files_>> - Import dive information from a file in
in a _Subsurface_-compatible format.
- <<S_Companion,_Import GPS data from Subsurface Service_>> - Load GPS
coordinates from the _Subsurface_ mobile phone app.
- <<S_ImportingDivelogsDe,_Import from Divelogs.de_>> - Import dive information
from _www.Divelogs.de_.

=== Log
- <<S_EnterData,_Add Dive_>> - Manually add a new dive to the *Dive List* panel.
- <<S_Renumber,_Renumber_>> - Renumber the dives listed in the *Dive List*
panel.
- <<S_Group,_Auto Group_>> - Group the dives in the *Dive List* panel into dive
trips.
- _Edit Device Names_ - Edit the names of dive computers.

=== View
- <<S_ViewPanels,_All_>> - View the four main _Subsurface_ panels
simmultaneously.
- <<S_ViewPanels,_Dive List_>> - View only the *Dive List* panel.
- <<S_ViewPanels,_Profile_>> - View only the *Dive Profile* panel.
- <<S_ViewPanels,_Info_>> - View only the *Dive Notes* panel.
- <<S_ViewPanels,_Globe_>> - View only the *World Map* panel.
- _Yearly Statistics_ - Display summary statistics about dives during the last
year.
- _Prev DC_ - Switch to next dive computer.
- _Next DC_ - Switch to previous dive computer.
- _Full Screen_ - Toggles Full Screen mode.

=== Filter
- _Select Events_ - This option is not implemented yet.

=== Help
- _About Subsurface_ - Show a panel with the version number of _Subsurface_ as
well as licensing information.
- _User Manual_ - Open a window showing this user manual.


== APPENDIX A: Operating system specific information for importing dive information from a dive computer.

=== Make sure that the OS has the required drivers installed
[icon="images/icons/drivers.jpg"]
[NOTE]
The operating system of the desktop computer needs the appropriate drivers in
order to communicate with the dive computer in whichever way the dive
computer prefers (e.g. bluetooth, USB, infrared).

	* On Linux this means users need to have the correct kernel
	  module loaded. Most distributions will do this automatically.

	* On Windows, the OS should offer to download the correct
	  driver once the user connects the dive computer to the USB port.

	* On a Mac users sometimes have to manually hunt for the correct
	  driver. For example the correct driver for the Mares Puck
	  devices can be found as Mac_OSX_VCP_Driver.zip at

http://www.silabs.com/support/pages/support.aspx?ProductFamily=USB+Bridges

[[S_HowFindDeviceName]]
=== How to Find the Device Name for USB devices and set its write permission
[icon="images/icons/usb.jpg"]
[NOTE]
When a user connects the dive computer by using a USB connector, usually
_Subsurface_ will either propose a drop down list that contains the
correct device name (or mount point for the Uemis Zurich), or it will
disable the device select drop down if no device name is needed at
all. In the rare cases where this doesn't work, here are some
instructions on ways to find out what the device name is:

.On Windows:

Simply try COM1, COM2, etc. The drop down list should contain all connected COM
devices.

.On MacOS:

The drop down box should find all connected dive computers.

.On Linux:

Try the following:

 - Disconnect the USB cable from the dive computer
 - Open a terminal
 - Type the command: 'dmesg' and press enter
 - Plug in the USB cable of the dive computer
 - Type the command: 'dmesg' and press enter

Within the terminal, users should see a message similar to this one:

	usb 2-1.1: new full speed USB device number 14 using ehci_hcd
	usbcore: registered new interface driver usbserial
	USB Serial support registered for generic
	usbcore: registered new interface driver usbserial_generic
	usbserial: USB Serial Driver core
	USB Serial support registered for FTDI USB Serial Device
	ftdi_sio 2-1.1:1.0: FTDI USB Serial Device converter detected
	usb 2-1.1: Detected FT232BM
	usb 2-1.1: Number of endpoints 2
	usb 2-1.1: Endpoint 1 MaxPacketSize 64
	usb 2-1.1: Endpoint 2 MaxPacketSize 64
	usb 2-1.1: Setting MaxPacketSize 64
	usb 2-1.1: FTDI USB Serial Device converter now attached to ttyUSB3
	usbcore: registered new interface driver ftdi_sio
	ftdi_sio: v1.6.0:USB FTDI Serial Converters Driver

Users can see that in the third line from the bottom, the USB adapter is
detected and is connected to +ttyUSB3+. This information can now be used in
the import settings as +/dev/ttyUSB3+. This directs Subsurface to the correct
USB port.

Ensuring you have write permission to the USB serial port:

On Unix-like operating systems the USB ports can only be accessed by users who
are members
of the +dialout+ group. If one is not root, one may not be a member of
that group and
will not be able to use the USB port. Let us assume one's username is 'johnB'.

 - As root, type: +usermod -a -G dialout johnB+  (Ubuntu users: +sudo -a -G
dialout johnB+)
This makes johnB a member of the +dialout+ group.
 - Type: +id johnB+     This lists all the groups that johnB belongs to and
verifies that
the appropriate group membership has been created. The +dialout+ group should
be listed
among the different IDs.

With the appropriate device name (e.g. +dev/ttyUSB3+) and with write permission
to the USB
port, the dive computer interface can connect and one should be able to import
dives.

[[S_HowFindBluetoothDeviceName]]
=== Setting up bluetooth enabled devices
[icon="images/icons/bluetooth.jpg"]
[NOTE]
For dive computers communicating through bluetooth like the Heinrichs
Weikamp Frog or the Shearwater Predator and Petrel there is a
different procedure to get the devices name to communicate with
_Subsurface_. In general it consists of these steps:

 * enable bluetooth on your computer
 * pairing the device

Do not forget to set your divecomputer in Bluetooth or upload mode before
Paring and Downloading logs. If you use a Shearwater Predator/Petrel just select
_Dive Log -> Upload Log_ and wait until you see the _Wait PC_ message.

.On Windows:

Bluetooth is most likely already enabled. For pairing the device choose
Control Panel->Bluetooth Devices->Add Wireless Device
This should bring up a dialog showing your dive computer (in Bluetooth mode) and
allowing to pair it. For bluetooth pairing of your dive computer refer to the
manufacturer's user guide. The dive computer should then show up in the list of
Bluetooth devices and you may then right click on it and choose Properties->COM
Ports to identify the port used for your dive computer. If there are several
ports listed, use the one saying "Outgoing" instead of "Incoming".

For downloading to _Subsurface_, the drop down list should contain this COM
port already. If not, enter it manually.

Note: If you have issues downloading from your dive computer in other software
afterwards try to remove the pairing with your dive computer.

.On MacOS:

Click on the Bluetooth symbol in the menu bar and select 'Set up
Bluetooth Device...'. Make sure that your dive computer is in upload
mode; it should then show up in the list of devices. Select it and go
through the pairing process. This step should only be needed once for
initial setup.

Once the pairing is completed the correct device will be shown in the
'Device or Mount Point' drop down in the _Subsurface_ *Import* dialog.

.On Linux
Ensure bluetooth is enabled on the _Subsurface_ computer.
On most common distributions this should be true out of the box. If not then
depending on your system, running +initd+ or +systemd+. This might be different
and also involve loading modules specific to your hardware. In case your system
is
running +systemd+, manually run +sudo systemctl start bluetooth.service+ to
enable
it, in case of +initd+, run something like +sudo rc.config start bluetoothd+ or
+sudo /etc/init.d/bluetooth start+.

Pairing should be straight forward. Using Gnome3 for instance will show a
bluetooth icon in the upper right corner of the desktop where one selects 'Set
up New Device'. This should show a dialog where one can select the
dive computer (in bluetooth mode) and pair it. For issues with PIN
setting try manually setting '0000'.

One may also use a manual approach by using such commands:

 * +sudo hciconfig+ - shows the bluetooth devices available on your
computer (not dive computer), most likely one will see a hci0, if not
try 'sudo hcitool -a' to see inactive devices and try to run 'sudo
hciconfig hci0 up' to bring them up

 * +sudo hcitool scanning+- use this to get a list of bluetooth enabled
client devices, look for the dive computer and remember the MAC
address shown there

 * +sudo bluez-simple-agent hci0 10:00:E8:C4:BE:C4+ - this will pair
the dive computer with the bluetooth stack of the _Subsurface_ computer, copy/paste
the MAC address from the output of 'hcitool scanning'

Unfortunately on Linux binding to a communication device has to be done
manually by running:

 * +sudo rfcomm bind /dev/rfcomm0 10:00:E8:C4:BE:C4+ - bind the dive
computer to a communication device in the desktop computer, in case rfcomm is
already taken just use rfcomm1 or up, please copy/paste the MAC address
from the output of 'hcitool scanning', the MAC shown in here will not
work.

For downloading dives in Subsurface one then has to specify +/dev/rfcomm0+
as device name to use.


== APPENDIX B: Dive Computer specific information for importing dive
information.


[[S_ImportUemis]]
=== Import from a Uemis Zurich

[icon="images/icons/iumis.jpg"]
[NOTE]
Things are very similar to a normal USB-connected dive computer when
downloading dives from a Uemis Zurich
dive computer (one of the ones that recharge when
connected to the USB port). The main difference is that one does not enter a
device name, but instead the location where the UEMISSDA file system is
mounted once you connect the dive computer. On Windows this is a drive letter (
often 'E:' or 'F:'), on a Mac this is
'/Volumes/UEMISSDA' and on Linux systems this differs depending on the
distribution. On Fedora it usually is
'/var/run/media/<your_username>/UEMISSDA'. In all cases _Subsurface_
should suggest the correct location in the drop down list.

Once onehas selected this as device name one can download the
dives from the Uemis Zurich. One technical issue with the Uemis Zurich
download implementation (this is a firmware limitation, not a
_Subsurface_ issue) is that one cannot download more than about 40-50
dives without running out of memory on the SDA. This will usually only
happen the very first time one downloads dives from the Uemis Zurich -
normally when downloading at the end of a day or even after a dive
trip, the capacity is sufficient. If _Subsurface_ displays an error
that the dive computer ran out of space the solution is straight
forward.  Disconnect the SDA, turn it off and on again, and reconnect
it. You can now retry (or start a new download session) and the
download will continue where it stopped previously. One
may have to do this more than once, depending on how many dives are
stored on the dive computer.

At this point _Subsurface_ downloads most of the information
stored on the SDA, including information about dive spots and
equipment. Buddy information is not yet downloadable.


[[S_ImportingDR5]]
=== Importing dives from Heinrichs Weikamp DR5

[icon="images/icons/HW_DR5.jpg"]
[NOTE]
When mounted as a USB drive the Heinrichs Weikamp DR5 saves a single UDDF file
for every dive.
Mark all the dives you'd like to import or open.
Note: The DR5 does not seem to store gradient factors nor deco information, so
for _Subsurface_ it is not possible to display them. Adjust the gradient
factors in the Tec Settings in _Subsurface_ to generate a deco overlay in the _
Subsurface_ *Dive Profile* panel
to get deco displayed but please note that the deco calculated by _Subsurface_
will most likely differ from the one displayed on the DR5.

=== Import from Shearwater Predator using bluetooth

[icon="images/icons/predator.jpg"]
[NOTE]
Using a Shearwater Predator you may be able to pair Bluetooth but then encounter
issues when downloading, showing errors like _Slip RX: unexp. SLIP END_ on the
Predator.
This might also be seen, when using other dive log software and operating
systems than Linux. We have no detailed idea about the source and how to fix
this, but it is reported to be solved sometimes by one of these steps:

 * use the bluetooth dongle which came with the Shearwater Predator instead of
   the built-in one of your computer
 * switch to different bluetooth drivers for your hardware
 * switch off WiFi while using Bluetooth


== APPENDIX C: Exporting Dive log information from external dive log software.

The import of dive log data from external dive log software is mostly performed
using
the dialogue found by selecting _Import_ from the Main Menu, then clicking on
_Import Log Files_. This is a single-step process, more information about which
can be found
xref:Unified_import[here.]
However, in some cases, a two-step process may be required:

 - Export the forieign dive log data to format that is accessible from
_Subsurface_.
 - Import the accessible dive log data into _Subsurface_.

This appendix provides some information about approaches to export dive log
data from foreign
dive log software. The procedures below mostly apply to Linux and/or Windows.

[[S_ImportingDivesSuunto]]
=== Exporting dives from *Suunto Divemanager (DM3 and DM4)*
[icon="images/icons/suuntologo.jpg"]
[NOTE]
Divemanager 3 (DM3) is an older version of the Suunto software. More recent
Suunto dive computers use Divemanager 4 (DM4). The
two versions of Divemanager use different methods and different file naming
conventions to export dive log data.

*Divemanager 3 (DM3):*

 - Start 'Suunto Divemanager 3' and log in with the name containing the logs
 - Do not start the import wizard to import dives from the dive computer.
 - In the navigation tree on the left side of the program-window, select the appropriate
dives.
 - Within the list of dives, select the dives you would like to import later:
	* To select certain dives: hold 'ctrl' and click the dive
	* To select all dives:  Select the first dive, hold down shift and
select the
last dive
 - With the dives marked, use the program menu 'File -> Export'
 - The export pop-up will show
 - Within this pop-up, there is one field called Export Path.
	* Click the browse button next to the field Export Path
		** A file-manager like window pops up
		** Navigate to the directory or storing the
Divelog.SDE file
		** Optionally change the name of the file for saving
		** Click 'Save'
	* Back in the Export pop-up, press the button 'Export'
 - The dives are now exported to the file Divelogs.SDE.

*Divemanager 4 (DM4):*

To import divelog from 'Suunto DM4', one needs to locate the DM4 database
where the dives are stored. the user can either look for the original
database or take a backup of the dives. Both methods are described here.

Locating the Suunto DM4 database:

 * Start Suunto DM4
 * Select 'Help -> About'
 * Click 'Copy' after text 'Copy log folder path to clipboard'
 * Now open Windows Explorer
 * Paste the address to the path box at the top of the File Explorer
 * The database is called DM4.db

Backing up Suunto DM4:

 * Start Suunto DM4
 * Select 'File - Create backup'
 * From the file menu select the location and name for the backup, we'll
   use DM4 in here with the default extension .bak
 * Click 'Save'
 * The dives are now exported to the file DM4.bak


=== Exporting from Mares Dive Organiser V2.1
[[Mares_Export]]

[icon="images/icons/mareslogo.jpg"]
[NOTE]
Mares Dive Organiser is a Microsoft application. The dive log is kept as a
Microsoft SQL Compact Edition data base with a .SDF filename extension. The
data base includes all Dive Organiser-registered divers on the particular
computer and all Mares dive computers used. The safest way to obtain a copy
of the dive data base is to export the information to another compatible format
which can be imported into _Subsurface_.

 - Within Dive Organiser, select
_Database -> Backup_ from the main menu and back up the data base to the desk
top.
This creates a zipped file DiveOrganiserxxxxx.dbf.
 - Rename the file to
DiveOrganiserxxxxx.zip. Inside the zipped directory is a file
_DiveOrganiser.sdf_.
 - Extract the _.sdf_ file from the zipped folder to your Desktop.

[[S_ImportingDivinglog]]
=== Exporting dives from *DivingLog 5.0*

[icon="images/icons/divingloglogo.jpg"]
[NOTE]
Unfortunately DivingLog XML files give us no
indication on the preferences set on one's system. So in order for
_Subsurface_ to be able to successfully import XML files from DivingLog
one first needs to ensure that DivingLog is configured
to use the Metric system (one can easily change this in 'File ->
Preferences -> Units and Language' by clicking the 'Metric'
button). Then do the following:

 - In Divinglog open the 'File -> Export -> XML' menu
 - Select the dives to export
 - Click on the export button and select the filename


== APPENDIX D: FAQs.

=== Subsurface appears to miscalculate gas consumption and SAC
[[SAC_CALCULATION]]
Not really. What happens is that subsurface actually calculates gas
consumption differently - and better - than you expect.
In particular, it takes the incompressibility of the gas into account.
Traditionally, Gas consumption and SAC should be:
+consumption = tank size x (start pressure - end pressure)+

and that's true for an ideal gas, and it's what you get taught in dive theory.
But an "ideal gas" doesn't actually exist, and real gases actually don't compress
linearly with pressure. Also, you are missing the fact that one atmosphere of
pressure isn't actually one bar.
So the *real* calculation is:

+consumption = (amount_of_air_at_beginning - amount_of_air_at_end)+

where the amount of air is *not* just "tank size times pressure in bar".
It's a combination of: "take compressibility into account" (which is a fairly
small issue under 220 bar - you'll see more differences when you do high-pressure
tanks with 300bar) and "convert bar to atm" (which is the majority of your discrepancy).
Remember: one ATM is ~1.013 bar, so without the compressibility, your gas use is:

+12.2*((220-100)/1.013)+

which is about 1445, not 1464. So there was 19 l too much in your simple
calculation that ignored the difference between 1 bar and one ATM.
The compressibility does show up above 200 bar, and takes that 1445 down
about eight liters more, so you really did use only about 1437 l of air at surface pressure.
The math details can be seen in dive.c:

+surface_volume_multiplier().+

The "if (bar > 200) bar = .." part is the compressibility - it's an approximation,
but it's a reasonably good one, and closer to reality than not doing it.
You can get the numbers you expect if you remove that, and turn the function into just:

+return pressure.mbar / 1000.0;+

but that would actually be wrong.
So be happy: your SAC really is better than your calculations indicated.
Or be sad: your cylinder contains less air than you thought it did.
And as mentioned, the "contains less air than you thought it did" really
starts becoming much more noticeable at high pressure. A 400 bar really does not
contain twice as much air as a 200 bar one. At lower pressures, air acts pretty much like an ideal gas.

=== Some dive profiles have time discrepances with the recorded samples from my dive computer...

_Subsurface_ ends up ignoring surface time for many things (average depth, divetime, SAC, etc).
 For example, if you end up doing a weight check (deep enough to trigger the "dive started")
but then come back up and wait five minutes for your buddies, your dive computer may say
that your dive is 50 minutes long - because you have fifty minutes worth of samples - but
subsurface will say it's 45 minutes - because you were actually diving for 45 minutes.
It's even more noticeable if you do things like divemastering the initial OW dives, when
you may stay in the water for a long time, but spend most of it at the surface. And then
 you don't want that to count as some kind of long dive”.