Welcome as a user of _subsurface_, an advanced dive logging programme with extensive infrastructure to describe, organise and interpret scuba and free dives. _subsurface_ runs on many hardware platforms and software environments. These include Linux (many distros), Mac (OS/X) and Windows (Win XP or later). 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 writing 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 README file included with the source code.
1) The *Dive List* to the bottom left containing a list of all the dives in your dive log. One can select and highlight a dive on the dive list by clicking on it.
One can drag the dividers between panels in order to change the size of any of the panels. _subsurface_ remembers the position of the dividers: if one launches _subsurface_, it uses the positions of the dividers when the program was executed previously.
You can determine which of the four panels you wish to see by selecting *View* option on the main menu and which gives the user several choices of display:
This is achieved by selecting _File -> New Logbook_ from the main menu. All existing dive data are cleared so that new information can be added. Existing dive data can be saved before a new logbook is created.
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].
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 written dive logbook includes dive type, date, time, duration of dive, depth of dive, name of buddy and of dive master and some remarks about the dive. _subsurface_ can store much more information than this for each dive. In order to add a dive to your dive log, click on _Log -> Add Dive_. 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. We will now consider each of the tabs used for data entry.
image::images/AddDive1.jpg["The most important parts of the _subsurface_ window for manual data entry",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 you are in the process of adding information about your dive. If one clicks on the *Dive Notes* tab, the following fields are visible:
The *Starttime* field contains five data items reflecting the date and the time of the dive. By clicking the down-arrow on the right of that field one can display a calendar from which you can choose the correct date. 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*: Type in the air and water temperatures during the dive into these fields to the right of the Starttime. You do not need to type in units of temperature: subsurface supplies these automatically, you only need type the number. (The units selected in the 'Preferences' [red]#[[URL link]]# will determine whether metric or imperial units are displayed)
*Location*: Here type in text that describes the site where you did this dive, e.g. "Lake Balaton, Hungary".
*Coordinates*: The geographic coordinates of the dive site should be entered here. These can come from three sources:
a. You can enter the coordinates by hand if you happen to know what they are. You need to enter them as decimal degrees, e.g: N30° 13.49760' , E30° 49.30788'.
b. You 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". Upon a double-click at the appropriate place, the green bar disappears and the coordinates are stored (Sometimes the coordinates are not shown in the Dive Notes immediately but only appear when you save the data for your dive). [red]#[[Bug??]]#
c. You can obtain the coordinates from a helper program if your mobile phone has a GPS and you stored the coordinates of the dive site on your mobile or tablet.
[red]#[[Text needs to be inserted here after the helper software has been completed]]#
*Divemaster*: Enter the name of the divemaster during the dive.
*Buddy*: Enter the name of your buddy during the dive.
*Suit*: Enter the type of diving suit you used for the dive. Your descriptions of diving suits are remembered within a particular logbook so that a similar description during later dives will re-use your original description, should you wish this to happen.
*Rating*: Here you can provide a subjective overall rating of the dive on a 5-point scale by clicking the appropriate star on the rating scale.
*Visibility*: You can provide a rating of visibility during the dive on a 5-point scale by clicking the appropriate star.
*Tags*: You may enter tags here (separate them by commas) that describe the type of dive you performed. Examples of common tags are boat, drift, training, cave. _subsurface_ has many built-in tags. If you start to type a tag, the program will list the tags that correspond to your typing. For instance, if you typed +cav+, then the tags *cave* and *cavern* are shown for the user to choose from.
*Notes*: Type any additional information here.
The *Save* and *Cancel* buttons are used to save all the information for the dive after all the other information has been added. Here is an example of a completed Dive Notes panel:
image::images/CompletedDiveInfo.png["Example: A completed Dive Notes tab",align="center"]
==== Equipment
The Equipment tab allows the user to enter information about the type of cylinder and gas you used, as well as the weighting for that dive. The message in a blue box at the top of the panel:
indicates that one is in the process of adding equipment information for the dive. 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 righthand panel).
The + icon at the top right allows one to add more cylinders for this dive. The dark dustbin icon on the left allows one to delete information for a cylinder.
Start by selecting a cylinder type. The AL80 cylinder is shown as the default cylinder type. If you wish to change this, click on the AL80. This will bring up a dropdown list, accessible through a down-arrow:
image::images/CylinderDataEntry2.png["The cylinder drop-down list button",align="center"]
Use the dropdown list to select the cylinder type you used for this dive. The *Size* of the cylinder as well as its working pressure (*WorkPress*) will automatically be shown in the dialogue.
Now you need to indicate the starting pressure and the ending pressure of the specified gas during your dive. The unit of pressure (metric/imperial) corresponds to the setting you chose in the preferences [red]#[[LINK]]#.
Finally you need to type in the gas mixture that you used. If you used air, you can enter 21% or leave the field blank. If you used nitrox or trimix, specify the percentage of oxygen and the percentage of helium. Leave any inappropriate fields empty. Add information for any additional cylinders by using the + icon at the top right hand. Here is an example of a complete description for a dive using two cylinders (air and EAN40):
image::images/CylinderDataEntry3.png["Example: a completed cylinder dive information table",align="center"]
*Weights*: Information about the weighting system used during a dive can be entered using a dialogue very similar to that of the cylinder information. If you click the + icon on the top right of the weights dialogue, the table looks like this:
If you click on the *Type* field, a dropdown list becomes accessible through a down-arrow:
image::images/WeightsDataEntry2.png["Weights type drop-down list button",align="center"]
Use the dropdown list to select your type of weighting system. In the *Weight* field, type in the weight used during the dive. It is possible to enter information for more than one weighting system by adding an additional system using the + icon on the top right hand. Weighting 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.png["Example: A completed weights information table",align="center"]
==== Creating a Dive Profile
The *Dive Profile* (a graphical representation of the depth of your dive as a function of time) is indicated in the panel on the top right hand of the _subsurface_ window. When you manually add a dive to your logbook, _subsurface_ presents a default dive profile that one needs to modify to best represent the dive being described:
_Configuring the dive profile_: When one moves the cursor around the dive profile, its position is indicated by two red lines as shown above. 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 [red]#[[LINK]]#. The dive profile itself comprises several line segments demarcated by waypoints (white dots on the profile, as shown above). The default dive depth is 15m. If your dive depth was 21m then you need to drag the appropriate waypoints downwards to represent 21m. To add a waypoint, double-clicking on any line segment. To remove a waypoint, right-click on it and choose "Remove this point" from the context menu. You will also need to drag the waypoints to represent an accurate time duration for your dive. Below is a dive profile that represents a dive to 21m for 31 min., followed by a 3 minute safety stop at 5m.
_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 performed by clicking on the gas description for a particular segment and selecting the appropriate choice from the context menu. Note that only the gases defined in the *Equipment* tab appear in the context menu:
If one inadvertently clicks on the gas composition but one does not wish to change this, press the ESCAPE keyboard button. Below is the profile of a dive to 21m 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.
The information entered in the *Dive Notes* tab, the *Equipment* tab as well as the dive profile can now be saved in your logbook by using the two buttons on the top right hand of the Dive Notes tab. If one clicks _Save_, the dive data are saved. If a logbook file hasn't been selected before, one can now select name and place to store the logbook otherwise it is saved in the already opened logbook. If one clicks _Cancel_, the newly entered dive data are deleted. When one exits _subsurface_ there is a final prompt to confirm that the new data should be saved.
The use of dive computers allows collecting a large amount of information about each dive, e.g. a detailed record of depth, durations, rates of ascent/descent and of gas partial pressures. _subsurface_ can capture this information and present it to you as part of the dive information. _subsurface_ can obtain 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].
To import dive information from a dive computer to your computer with _subsurface_, it is necessary that the two pieces of equipment must communicate. In order to set up this communication, you need to find the appropriate information to instruct _subsurface_ where and how to import the dive information. *Appendix A* provides the technical information to help you achieve this for different operating systems and *Appendix B* has divecomputer specific information.
Often, dive computers retain all their dives even though these dives have been imported to _subsurface_. However it is not necessary to import dives that have already been imported previously. For that reason _subsurface_ only imports dives that have not been uploaded before. This is beneficial for saving the battery power of your dive computer. If, for some reason, one wishes to import ALL dives in the dive computer, one can tick the box labeled _Force download of all dives_.
- The dialogue has two drop-down lists, *Vendor* and *Dive Computer*. On the *vendor* drop-down list select the make of your computer, e.g. Suunto, Oceanic, Uwatec, Mares. On the *Dive Computer* drop-down list, select the model name of your dive computer, e.g. D4 (Suunto), Veo200 (Oceanic), or Puck (Mares).
- The *Device or Mount Point* dropdown list contains the USB or Bluetooth port name that _subsurface_ needs in order to communicate with your dive computer. Select the appropriate port name. Consult *Appendix A* for technical details to find the appropriate port information for your dive computer and, in some cases, to do the correct settings to the operating system of your _subsurface_ computer.
- If there is a problem in communicating with your dive computer, an error message will be shown, similar to this text: "Unable to open /dev/ttyUSB0 Mares (Puck Pro)". In this case, consult *Appendix A* for information specific to the operating system of your _subsurface_ computer and consult *Appendix B* for information specific to some dive computers.
When download of the dive information is complete, all the imported dives appear on your Dive List, sorted by date and time. Switch off your dive computer to conserve its battery power.
If one selects a particular dive, the Dive Profile panel shows an informative graph of dive depth against time for that particular dive.
The information from your dive computer is not complete and one needs to add more details in order to have a more complete record of your dives. To do this, use the *Dive Notes* and the *Equipment* tabs on the top left hand of the _subsurface_ window.
The date and time of the dive, gas mixture and perhaps water temperature is shown as obtained from the dive computer, but one needs to add some information by hand in order for a more complete dive record. The message in a blue box at the top of the panel indicates that one is in the process of adding information about a dive. If one clicks on the *Dive Notes* tab, the following fields are visible:
The *Starttime* field contains five data items reflecting 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 one can display a calendar from which you can choose the correct date. 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 editing. If editing is required, one does not need to type in units of temperature: subsurface supplies these automatically, only a number is required. (The units selected in the 'Preferences' [red]#[[URL link]]# will determine whether metric or imperial units are displayed)
a. You can enter the coordinates by hand if you happen to know what they are. You need to enter them as decimal degrees, e.g: N30° 13.49760', E30° 49.30788'.
b. You 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". Upon a double-click at the appropriate place, the green bar disappears and the coordinates are stored (Sometimes the coordinates are not shown in the Dive Notes immediately but only appear when you save the data for your dive). [red]#[[Bug??]]#
c. You can obtain the coordinates from a helper program if your mobile phone has a GPS and you stored the coordinates of the dive site on your mobile or tablet.
[red]#[[Text needs to be inserted here after the helper software has been completed]]#
*Divemaster*: Enter the name of the divemaster during the dive.
*Buddy*: Enter the name of your buddy during the dive.
*Suit*: Enter the type of diving suit you used for the dive. Your descriptions of diving suits are remembered within a particular logbook so that a similar description during later dives will re-use your original description, should you wish this to happen.
*Rating*: Here you can provide a subjective overall rating of the dive on a 5-point scale by clicking the appropriate star on the rating scale.
*Visibility*: You can provide a rating of visibility during the dive on a 5-point scale by clicking the appropriate star.
*Tags*: You may enter tags here (separate them by commas) that describe the type of dive you performed. Examples of common tags are boat, drift, training, cave. _subsurface_ has many built-in tags. If you start to type a tag, the program will list the tags that correspond to your typing. For instance, if you typed +cav+, then the tags *cave* and *cavern* are shown for the user to choose from.
*Notes*: Type any additional information here.
The *Save* and *Cancel* buttons are used to save all the information for the dive after all the other information has been added. Here is an example of a completed Dive Notes panel:
image::images/CompletedDiveInfo.png["Example: A completed Dive Notes tab",align="center"]
==== Equipment
The Equipment tab allows the user to enter information about the type of cylinder and gas you used, as well as the weighting for that dive. The message in a blue box at the top of the panel:
indicates that one is in the process of adding equipment information for the dive. 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 righthand panel).
The + icon at the top right allows one to add more cylinders for this dive. The dark dustbin icon on the left allows one to delete information for a cylinder.
Start by selecting a cylinder type. The AL80 cylinder is shown as the default cylinder type. If you wish to change this, click on the AL80. This will bring up a dropdown list, accessible through a down-arrow:
image::images/CylinderDataEntry2.png["The cylinder drop-down list button",align="center"]
Use the dropdown list to select the cylinder type you used for this dive. The *Size* of the cylinder as well as its working pressure (*WorkPress*) will automatically be shown in the dialogue.
Now you need to indicate the starting pressure and the ending pressure of the specified gas during your dive. The unit of pressure (metric/imperial) corresponds to the setting you chose in the preferences [red]#[[LINK]]#.
Finally you need to type in the gas mixture that you used. If you used air, you can enter 21% or leave the field blank. If you used nitrox or trimix, specify the percentage of oxygen and the percentage of helium. Leave any inappropriate fields empty. Add information for any additional cylinders by using the + icon at the top right hand. Here is an example of a complete description for a dive using two cylinders (air and EAN40):
image::images/CylinderDataEntry3.png["Example: a completed cylinder dive information table",align="center"]
*Weights*: Information about the weighting system used during a dive can be entered using a dialogue very similar to that of the cylinder information. If you click the + icon on the top right of the weights dialogue, the table looks like this:
If you click on the *Type* field, a dropdown list becomes accessible through a down-arrow:
image::images/WeightsDataEntry2.png["Weights type drop-down list button",align="center"]
Use the dropdown list to select your type of weighting system. In the *Weight* field, type in the weight used during the dive. It is possible to enter information for more than one weighting system by adding an additional system using the + icon on the top right hand. Weighting 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.png["Example: A completed weights information table",align="center"]
==== Saving the updated dive information
The information entered in the *Dive Notes* tab, the *Equipment* tab can be saved with all the other information of your dives in your logbook by using the two buttons on the bottom right hand of the Dive Notes tab. If one clicks Save, the dive data are saved. If one clicks Cancel, the newly entered dive data are deleted, although the dive profile obtained from the dive computer will be retained. When one exits _subsurface_ there is a final prompt to confirm that the new data should be saved.
Mares Dive Organiser is a Windows 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 this data base is, within Dive Organiser, to select Database -> Backup from the main menu and to back up the data base to your 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 it from the zipped folder to your Desktop.
Then use _www.divelogs.de_ as a mechanism to extract the dive information from the file. Create a user account in divelogs.de , then select Import Logbook -> Dive Organiser from the menu on the left hand side. Follow the instructions carefully to transfer the information from the Dive Organiser data base to divelogs.de.
Then follow the instructions below to import dives from divelogs.de to _subsurface_.
[red]#Needed here: Careful check of the current accuracy of the information and detail description of import from other digital sources, divelogs.de etc.#
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 oxygen toxicity units (OTU) incurred.
The Stats tab gives summary statistics for more than one dive, assuming that more than one dive have been selected in the *Dive List*. Select more than one dive by 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).
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 rate compared to the recommended speed of going up or down in the water column. This information is given using different colors:
The profile also includes depth readings for the peaks in the graph. Thus you 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 tank pressure gives you information about the momentary SAC rate (Surface Air Consumption – often also called RMV – Respiratory Minute Volume) when using an air integrated dive computer. Here the color coding is not relative to some absolute values but relative to the average normalized 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 color 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 degree markings 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.
Measurements of *depth differences* can be achieved by using the button with two vertical bars at the right of the dive profile panel (see above figure, bottom right). Drag the red dots to the two points on the dive profile which you would like to measure. Information is 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 you 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 – note 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 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, _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 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 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/InfoBox.png["Figure: Information Box",align="centre"]
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 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, cylider pressure (P), temperature, ascent/descent rate, surface air consumption (SAC), oxygen partial pressure, maximum operating depth, effective air depth (EAD), effective nitrigen depth (END), equivalent air density depth (EADD), Decompression requirements at that instand 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)
Many actions within _subsurface_ are dependent on a context menu that is 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.
The context menu is used in many manipulations described below.
=== 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 sometimes needs to renumber the dives. This is performed by selecting (from the Main menu) Log -> Renumber. You 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.
If one dives regularly, 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 (on the left) as well as a grouped dive list with several trips (on the right):
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) 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, one 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. One can add much more information about a trip by selecting its trip title from the dive list. This shows a *Trip Notes* tab in the *Dive Notes* panel. Here you can add or edit information about the date/time, the trip location and any other general comment about the trip as a whole (e.g. the dive company you dived with, the general weather during the trip). After entering this information, select *Save* from the buttons at the bottom 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 one 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
When one right-clicks on a selected trip title in the *Dive List* panel, the context menu 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, one 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 one create a new trip by choosing the option *Create new trip above*. The top three dives are then grouped into a separate trip. See below, the selection and context menu on the left, the completed action on the right:
image::images/SplitDive3a.png["Example: 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*. Typically this would apply to a case where one wishes to delete workshop calibration dives of the dive computer or dives of extremely short duration.
=== Unlink a dive from a trip
One can unlink dives from the trip to which they belong. Select and right-click the dives to bring up the context menu. Then select *Remove dive(s) from trip*. 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. Select and right-click the dives to bring up the context menu, then select *Add dive(s) to trip immediately above*.
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. Select and right-click the dive(s) to be adjusted. This brings up the context menu. Select *Shift times*. 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.
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. One can merge these dives onto a single dive by selecting the appropriate dives and right-clicking them to bring up the context menu. Then select *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:
== 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). See 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), select *File* from the Main menu. To save in _subsurface_ XML format, select _File -> Save as_. To save in UDDF format, select _File -> Export UDDF_.
In order to save only one or more dives or one or two trips, select the appropriate dives or trips in the *Dive List* panel. Then right-click the selected dives to bring up the context menu. To save in _subsurface_ XML format, select _Save as_ from the context menu. To save in UDDF format, select _Export as UDDF_ from the context menu.
There are several settings within _subsurface_ that the user can specify. These are found when selecting _File->Preferences_. The settings are performed in three groups: *Defaults*, *Units* and *Graph*. All three sections operate on the same principles: specify the settings you wish to change, then save these using the *Apply* button. After applying the new settings one can leave the settings panel by selecting *OK*.
=== Defaults
There are four settings in the *Defaults* panel:
** *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,
one can see more dives on a screen.
** *Dives*: Here one needs to specify the directory and file name of your electronic dive log book. This is a file with filename extension .xml. _subsurface_ will then automatically load the dive log book specified.
** *Use Default cylinder*: Here one can specify the default cylinder listed in the *Equipment* tab of the *Dive Notes* panel.
=== Units
Here one can choose between metric and imperial measures of depth, pressure, volume, temperature and mass. By selecting the Metric or Imperial radio button at the top, one can specify that all units are in the chosen measurement system. Alternatively, if one selects the *Personalise* radio button, one can select a mixture with some measurements being metric while others are in imperial measures.
=== Graph
This panel allows two type of selections:
* *Show*: Here one specifies the amount of information that is shown as part of the dive profile:
** Gas pressure graphs: _subsurface_ can display the pressures of the gases with which you dive. If you dive breathing air, then the only important gas is nitrogen. You can instruct _subsurface_ to plot the nitrogen pressure during your dive. If you dive breathing nitrox, then you can select a graph of both the nitrogen and oxygen pressures during your dive. If you dive with trimix or heliox, you can select the display of the helium pressure as well. For each of these graphs you 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 exposes the diver to 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 one checks *show all tissues*, the ceiling is shown for the tissue compartments following the Bühlmann model (*B* in figure below).
*** If one checks *3m increments*, then the ceiling is indicated in 3m-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 _Effective 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 specifies in the appropriate text box. In addition, if a _no-decompression limit(NDL)_ is to be shown in the *info* box, then check the appropriate box.
image::images/Ceilings.png["Figure: Ceiling with 3m resolution",align="center"]
* *Misc*: Here one can set the _gradient factors_ used while diving. GF_Low is the gradient factor at deep depths and GF_High is used just below the surface. At intermediate depths gradient factor 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 lower 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.]
== Importing GPS coordinates with Subsurface companion.
If you have an Android device with GPS, you can achieve the coordinates of the point where you are diving and automatically pass them to your Subsurface divelog. You only need:
- [red]#Register in Subsurface companion page.# http://api.hohndel.org/login/ You'll receive a confirmation mail with instructions and your *DIVERID*, this id will give you access to the companion app capabilities.
- [red]#Download the app.# You can download it from https://play.google.com/store/apps/details?id=org.subsurface or http://f-droid.org/repository/browse/?fdfilter=subsurface&fdid=org.subsurface .
=== Using Subsurface companion app.
On first use the app has three options:
* +Create a new account.+ Equivalent to register in Subsurface companion page.
* +Retrieve an account.+ This is the option you would use if someway have forgot your DIVERID. You should receive an email whith it.
* +Use an existing account.+ You'll be prompted to introduce your DIVERID.
The app stores your ID and don't ask for it again unless you use the _Disconnect_ menu option commented below.
Now you're ready to get a dive position and send it to the server. The android display will look like next image, but without any dive.
image::images/companion_1.png["Entry display for companion app",align="center"]
Typing the "+" icon on the right you will be prompted for a name for the dive point (or asked first for the GPS activation if this was turned off), and you will get a register in the display with the name of the dive point, date and time. As you can see in the image above, there are two kind of register, those with a little arrow up and those without it. The arrow up means the dive is stored in the device, but hasn't been sent to the server.
Now we want to send the dive to the server. There are several ways of doing this. Easiest is simply selecting the dive as seen in this image
and typing the right arrow will send it to the server. Be careful, the trash on the right means exactly what it's supossed to mean, it would delete de dive point.
Well, the new dive point is stored in the server and can be downloaded to Subsurface divinglog whenever you register your dive in it. If returning from a dive trip, and you have been lucky, there can be lots of dive points coordinates ready to be saved on your divelog. We will see how to do this later.
Next step would be adjust your preferences in the _Settings_ menu option. Let's see the options we would get by opening the menu.
- +User ID.+ Obtained by registering as indicated above. The easiest way to introduce it is simply copy+paste from the confirmation mail but, off course, you can type it char by char.
===== Synchronization
- +Synchronize on startup.+ If selected, dives in android device and those on the web service will synchronize each time you start the app.
- +Upload new dives.+ If selected, each time you add a dive it'll automatically be sent to the server.
===== Background service
Instead of take a unique position, you can leave the service running on background on your device. This setting will define the behaviour of the service.
- +Min duration.+ In minutes. The app'll try to get a position each X minutes until you stop it.
- +Min distance.+ In meters. Minimum distance between two position fixes.
- +Name template.+ Te name the app'll use when saving the position fixes.
[NOTE]
_How background service works?_ Let's asume we've set 5 minutes and 50 meters in the parameters above, the app will fix a position, then another one each 5 minutes. If this 2nd (3rd, 4th ...) is in a radius of 50 meters from the previous one, the position won't be saved. After another 5 minutes there will be a new try, and so on. This way, if we are in a static position, we'll only get a fix, but if we're moving we can have a nice trace of our journey.
===== Other
- +Mailing List.+ The mail box for Subsurface. You 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 you can search your saved dive points by the name you gave them or by date and hour.
==== Start service
Initiates the _background service_. It'll work depending on the previously fixed settings.
==== Disconect
Badly named option. It disconects your app from the server by reseting your ID in the app. It will send you to the first display where can create an account, retrive the ID for an existing one or use your own ID. Useful if you are downloading the dive positions for another registered user with your android device.
==== Send all locations
As expected, this option will send all locations stored in the android device to the server.
=== Downloading dive locations to your Subsurface divelog
First you will have downloaded your dive/s from your DC or created them manually. Now you want to get the GPS coordinates from the server. The download dialog can be reached via _Ctrl+G_ or from Subsurface's main menu _Import -> Import GPS data from Subsurface Service_
On first use the DIVERID will be blanked, so you'll have to put it here as usual. Then simply clik on the _Download_ button and the download begins. When ended you'll get the next
Note the _Apply_ button now active, click on it and, luckily, you'll be done. Subsurface's logic should apply the coordinates and names you gave them for all the new dives.
[NOTE]
_Features, issues and tips._ Automatically applying of GPS data to the dives is a task very dependent on a correct time. Note that there might be a difference between time in your DC and time in your android device, if you have a little one there'll be no problem and the logic will work fine, but if it's big Subsurface will be unable to identify the dive which matches the coordinates, and nothing will happen. The ideal is have a correct time in your DC (or in the android device, whichever is wrong) but this may be not possible. A dirty hack is editing manually the time in Subsurface's log _before_ downloading the GPS data. If the correct time was the erased one, then simply edit it back manually again _after_ downloading.
* Importing data from other electronic resources - Present information comes from subsurface 3.1.1 manual. How much of it is still valid? Needs to be verified.
* Importing data from dive computers - Appendices A and B come mainly from subsurface 3.1.1 manual. How much of it is still valid? Needs to be verified. Difficult work, but **critical** for the success of subsurface.
