<img src="images/WeightsDataEntry3_f20.jpg" alt="FIGURE: A completed weights information table" />
</div>
</div>
</div>
</div>
<div class="sect3">
<h4 id="_editing_several_selected_dives_simultaneously">5.2.5. Editing several selected dives simultaneously</h4>
<div class="paragraph"><p><em>METHOD 1</em>: After uploading dives from
a dive computer, the dive profiles of each is shown in the <strong>Dive profile</strong> tab, as well
as a few items of information
in the <strong>Notes</strong> tab (e.g. water temperature) and in the <strong>Equipment</strong> tab (e.g. gas pressures
and gas composition). Other fields remain empty.
It may be useful to simultaneously edit some of the
fields in the <strong>Notes</strong> and <strong>Equipment</strong> tabs. For instance, it’s possible
that a diver performed several dives during a single day, using identical equipment at the same
dive site, or with the same divemaster and/or buddy or tags. Instead
of completing the information for each
dive separately, select all the dives for that day in the <strong>Dive List</strong> and
insert the same information in the <strong>Notes</strong> and <strong>Equipment</strong> fields that need
identical information. This is done by editing the dive notes or the equipment for any one
of the selected dives.</p></div>
<div class="paragraph"><p>Simultaneous editing only works with fields that do not already contain information.
This means if some fields have been edited for a particular dive among the selected dives,
these are not changed while
editing the dives simultaneously. Technically, the rule for editing several dives simultaneously is:
if the data field being edited contains <em>exactly the same information</em> for all the dives that have been
selected, the new, edited information is substituted for all the selected dives. Otherwise only the
edited dive is
changed, even though several dives have been selected in the <strong>Dive List</strong>. This speeds
up the completion of the dive log after several similar dives.</p></div>
<div class="paragraph" id="S_CopyComponents"><p><em>METHOD 2</em>:There is a different way of achieving the same goal. Select a dive with all the appropriate information
typed into the <strong>Notes</strong> and <strong>Equipment</strong> tabs. Then, from the main menu, select <em>Log → Copy dive components</em>.
A box is presented with a selection of check boxes for most of the fields in the <strong>Notes</strong> and <strong>Equipment</strong> tabs.
Select the fields to be copied from the currently selected dive, then select <em>OK</em>. Now, in the <strong>Dive List</strong>,
select the dives
into which this information is to be pasted. Then, from the main menu, select <em>Log → Paste dive components</em>.
All the selected dives now contain the data initially selected in the original source dive log.</p></div>
</div>
<div class="sect3">
<h4 id="_adding_bookmarks_to_a_dive">5.2.6. Adding Bookmarks to a dive</h4>
<div class="paragraph"><p>Many divers wish to annotate dives with text that indicate particular events,
e.g. "Saw dolphins", or "Released surface buoy". This is easily
done:</p></div>
<div class="ulist"><ul>
<li>
<p>
Right-click at the appropriate point on the dive profile.
This brings up the dive profile context menu. Select <em>Add bookmark</em>. A red flag is
placed on the dive profile at that point (see <strong>A</strong> below).
</p>
</li>
<li>
<p>
Right-click on the red flag. This brings up the context menu (see <strong>B</strong> below). Select <em>Edit name</em>.
</p>
</li>
<li>
<p>
A text box is shown. Type the explanatory text for the bookmark (see <strong>C</strong> below). Select <em>OK</em>.
This saves the text associated with the bookmark.
</p>
</li>
<li>
<p>
Hovering the mouse over the red bookmark, the appropriate text is shown at
the bottom of the information box (see <strong>D</strong> below).
<h4 id="_saving_the_updated_dive_information">5.2.7. Saving the updated dive information</h4>
<div class="paragraph"><p>The information entered in the <strong>Notes</strong> tab and the <strong>Equipment</strong> tab can be
saved by using the
two buttons on the top right hand of the <strong>Notes</strong> tab. If the <em>Apply changes</em> button
is clicked,
the dive data are saved in the memory image of the dive. If the <em>Discard changes</em>
button is clicked, the newly entered dive data are
erased from the computer memory, although the dive profile is
retained. When the user exits <em>Subsurface</em> there is a final prompt to confirm
the new data should now be saved permanently on the computer disk.</p></div>
</div>
</div>
<div class="sect2">
<h3 id="_importing_dive_information_from_other_digital_data_sources_or_other_data_formats">5.3. Importing dive information from other digital data sources or other data formats</h3>
<div class="paragraph" id="S_ImportingAlienDiveLogs"><p>If you’ve been diving for some time, it’s possible several dives were
logged using other dive log software. These dive logs can probably be
imported into <em>Subsurface</em>. <em>Subsurface</em> will import dive logs from a range of
other
dive log software. While some software is supported natively, for
others you will need to
export the logbook(s) to an intermediate format so they can then be imported
by <em>Subsurface</em>.
Currently, <em>Subsurface</em> supports importing CSV log files from several sources.
APD LogViewer, XP5, Sensus and Seabear files are
preconfigured, but because the import is flexible, users can configure their own
imports.
Manually kept log files (e.g. a spreadsheet) can also be imported by
configuring the CSV import.
<em>Subsurface</em> can also import UDDF and UDCF files used by some dive log
software and some dive computers, like the Heinrichs & Weikamp DR5. Finally,
for some dive log software like Mares Dive Organizer we currently recommend you
import the logbooks first into a web service like <em>divelogs.de</em> and then import
from there with
<em>Subsurface</em>. Divelogs.de supports a few additional logbook formats that
<em>Subsurface</em> currently cannot handle.</p></div>
<div class="paragraph"><p>If the format of other software is supported natively on Subsurface, select
either <em>Import → Import log files</em> or <em>File → Open log file</em>. <em>Subsurface</em> supports the data formats
of many dive computers, including Suunto and Shearwater. When importing dives, <em>Subsurface</em>
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) <em>Subsurface</em>
will not create duplicate entries. Below is more specific information
to import data to <em>Subsurface</em>.
==== Using the universal import dialogue</p></div>
<div class="paragraph" id="Unified_import"><p>Importing dives from other software is done through a universal interface
activated by selecting <em>Import</em> from the Main Menu, then clicking on
<em>Import Log Files</em>. This brings up dialogue <strong>A</strong>, below.</p></div>
<img src="images/iphone.jpg" alt="FIGURE: Using iPhone companion application" width="640" />
</div>
</div>
<div class="paragraph"><p>Dives can be added automatically or manually. In manual mode, a dive location or waypoint is added to the GPS input stream. In automatic
mode, a continuous path of GPS locations is created from which,
after import, Subsurface can select the appropriate GPS
locations based on the times of dives. The default mode for the
<em>iphone</em> is automatic. When adding a dive, the
location service is started automatically and a red bar appears at the bottom
of the screen. After the dive, click on the red
bar to end the location service. While the location
service is running you can only add dives manually.</p></div>
<div class="paragraph"><p>You can edit the site name afterwards by selecting the dive
from the dive list and clicking on the site name. There are no other
editable fields. The dive list is automatically uploaded from the iPhone
to the web service. There isn’t an option to
trigger upload manually.</p></div>
</div>
<div class="sect3">
<h4 id="_downloading_dive_locations_to_the_em_subsurface_em_divelog">5.4.4. Downloading dive locations to the <em>Subsurface</em> divelog</h4>
<div class="paragraph"><p>Download dive(s) from a dive computer or enter them manually into
<em>Subsurface</em> before obtaining the GPS coordinates from the server. The download
dialog can be reached via <em>Ctrl+G</em> or from the <em>Subsurface</em> Main Menu <em>Import
→ Import GPS data from Subsurface Service</em>, resulting in the image on the
left (<strong>A</strong>), below. On first use the DIVERID text box is blank. Provide a
DIVERID, then select the <em>Download</em> button to start the download process, after
which the screen on the right (<strong>B</strong>) below appears:</p></div>
<div class="paragraph"><p>Note that the <em>Apply</em> button is now active. By clicking on it, you can update the locations
of the newly entered or uploaded dives in <em>Subsurface</em>. That applies the
coordinates and names entered on the app to all the new dives that match the
date-times of the uploaded GPS localities. If you have entered the name of the dive
location in <em>Subsurface</em> before downloading the GPS coordinates, this name will take
precedence over downloaded one.</p></div>
<div class="paragraph"><p>Since <em>Subsurface</em> 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 depends
on agreeing date-time information between the two devices. Although <em>Subsurface</em> has
a wide range tolerance, it may not be able to identify the appropriate dive if there’s
a large difference between the time in the dive computer and that of the Android device.
That results in no updates.</p></div>
<div class="paragraph"><p>Similar date-times may not always be possible and there may be many reasons for this (e.g. time zones).
<em>Subsurface</em> may also be unable to decide which is the correct position for a dive (e.g. on repetitive
dives while running <em>background service</em> there may be several locations that would be
included in the time range that fit not only the first dive, but one or more subsequent dives as well).
A workaround to manually edit the date-time of a dive in the <em>Subsurface</em>
Dive List <strong>before</strong> downloading the GPS data and then to change the date-time back again <strong>after</strong>
downloading GPS data.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="images/icons/info.jpg" alt="Note" />
</td>
<td class="content">TIPS:</td>
</tr></table>
</div>
<div class="ulist"><ul>
<li>
<p>
<em>Background service</em> may fill the location list with
unnecessary locations that don’t correspond to the exact dive point but do correspond to the boat’s route.
Right now, these locations are difficult to delete from the server. In some situations it
is better to clean up the list on the Android device before sending the dive points to the web
server by simply deleting the inappropriate locations. This might be necessary, for
instance, if you want to keep the location list clear to see dives in the web service map display (see above).
</p>
</li>
<li>
<p>
It may also make sense to give informative names to the locations sent to the web server, or at least
to use an informative name in the <em>Name Template</em> setting while running the <em>background service</em>,
especially on a dive trip with many dives and dive locations.
</p>
</li>
</ul></div>
</div>
</div>
<div class="sect2">
<h3 id="S_LoadImage">5.5. Adding photographs to dives</h3>
<div class="paragraph"><p>Many (if not most) divers take a camera with them and take photographs
during a dive. To match each photograph with a specific
dive, <em>Subsurface</em> lets you load photos into a dive. Photos are superimposed
on the dive profile, from where they can be viewed.</p></div>
<div class="sect3">
<h4 id="_loading_photos_and_synchronizing_between_dive_computer_and_camera">5.5.1. Loading photos and synchronizing between dive computer and camera</h4>
<div class="paragraph"><p>Left-lick on a dive or on a group of dives on the dive list. Then right-click on this
dive or group of dives and choose the option <em>Load Images</em>:</p></div>
<div class="paragraph"><p>More equipment-specific information for downloading CCR dive logs for
Poseidon MkVI and APD equipment can be found in <a href="#_appendix_b_dive_computer_specific_information_for_importing_dive_information">Appendix B</a>.</p></div>
</div>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_obtaining_more_information_about_dives_entered_into_the_logbook">6. Obtaining more information about dives entered into the logbook</h2>
<div class="sectionbody">
<div class="sect2">
<h3 id="_the_strong_info_strong_tab_for_individual_dives">6.1. The <strong>Info</strong> tab (for individual dives)</h3>
<div class="paragraph"><p>The Info tab gives some summary information about a particular dive that
has been selected in the <strong>Dive List</strong>. 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.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="images/icons/info.jpg" alt="Note" />
</td>
<td class="content">Gas consumption and SAC calculations:
<em>Subsurface</em> 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 <a href="#SAC_CALCULATION">Appendix F</a> for more information.</td>
</tr></table>
</div>
</div>
<div class="sect2">
<h3 id="S_ExtraDataTab">6.2. The <strong>Extra Data</strong> tab (usually for individual dives)</h3>
<div class="paragraph"><p>When using a dive computer, it often reports several data items that cannot easily be
presented in a standardised way because the nature of the information differs from one
dive computer to another. These data often comprise setup information, metadata about
a dive, battery levels, no fly times, or gradient factors used during the dive. When
possible, this information is presented in the <strong>Extra Data</strong> tab. Below is an
image showing extra data for a dive using a Poseidon rebreather.</p></div>
<td class="content">If, in addition, the <strong>3m increments</strong> button on the Profile Panel is clicked, then the ceiling is indicated in 3 m increments
<img src="images/ShowCylinders_f20.jpg" alt="Figure: Cylinder use graph" />
</div>
</div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="images/tissues.jpg" alt="Note" />
</td>
<td class="content">Display inert gas tissue pressures relative to ambient inert gas pressure (horizontal grey line).
Tissue pressures are calculated using the Bühlmann ZH-L16 algorithm and are displayed as lines ranging from
green (faster tissues) to blue (slower tissues).
The black line, graphed above the ambient pressure, is the maximum allowable tissue supersaturation (pressure limit) derived
from the gradient factors specified in the <strong>Preferences</strong>. For
divers doing planned decompression diving, efficient rates of offgassing are obtained with tissue pressures
between the ambient inert gas pressure (grey line) and the pressure limit (black line). This display is a representation
of the tissue pressures during the whole dive. In contrast, the <a href="#S_gas_pressure_graph">Gas Pressure Graph</a> in the <strong>Information Box</strong>
on the <strong>Dive Profile</strong> is an instantaneous reflection of tissue pressures at the moment in
time, at the position of the cursor on the dive profile.</td>
<img src="images/tissuesGraph.jpg" alt="Figure: Inert gas tissue pressure graph" />
</div>
</div>
<div class="paragraph"><p>Gradient Factor settings strongly affect the calculated ceilings and their depths.
For more information about Gradient factors, see the section on <a href="#S_GradientFactors">Gradient Factor Preference settings</a>. The
currently used gradient factors (e.g. GF 35/75) are shown above the depth profile if the appropriate toolbar buttons are activated.
<strong>N.B.:</strong> The indicated gradient factors are NOT the gradient factors in use by the dive computer,
but those used by <em>Subsurface</em> to calculate deco obligations
during the dive. For more information external to this manual see:</p></div>
<div class="ulist"><ul>
<li>
<p>
<a href="http://www.tek-dive.com/portal/upload/M-Values.pdf">Understanding M-values by Erik Baker, <em>Immersed</em> Vol. 3, No. 3.</a>
</p>
</li>
<li>
<p>
<a href="http://www.rebreatherworld.com/general-and-new-to-rebreather-articles/5037-gradient-factors-for-dummies.html">Gradient factors for dummies, by Kevin Watts</a>
</p>
</li>
</ul></div>
</div>
<div class="sect2">
<h3 id="_the_dive_profile_context_menu">6.5. The Dive Profile context menu</h3>
<div class="paragraph"><p>The context menu for the Dive Profile is accessed by right-clicking while the
mouse cursor is over the Dive Profile panel. The menu lets you create
Bookmarks, Gas Change Event markers, or manual CCR set-point changes
other than the ones that might have been
imported from a Dive Computer. Markers are placed against the depth profile line,
with the time of the event set by where the mouse cursor was when the right
mouse button was first clicked to bring up the menu. Gas Change events
involve a selection of which gas is being switched TO. The list of choices is based on
the available gases defined in the <strong>Equipment</strong> Tab. Setpoint change
events open a dialog letting you choose the next setpoint value. As
in the planner, a setpoint value of zero shows the diver is
breathing from an open circuit system while any non-zero value
shows the use of a closed circuit rebreather (CCR).
By right-clicking while over
an existing marker a menu appears, 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.</p></div>
</div>
<div class="sect2">
<h3 id="S_InfoBox">6.6. The <strong>Information Box</strong></h3>
<div class="paragraph"><p>The Information box displays a large range of information about the dive
profile. Normally the Information Box is located to the top left of the <strong>Dive
Profile</strong> panel. If the mouse points outside of the <strong>Dive Profile</strong> panel, then
only the top line of the Information Box is visible (see left-hand part of
figure (<strong>A</strong>) below). The Information Box can be moved around in the <strong>Dive Profile</strong>
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
<div class="paragraph"><p>The context menu is used in many functions described below.</p></div>
<div class="sect3">
<h4 id="_customizing_the_columns_showed_in_the_strong_dive_list_strong_panel">7.1.1. Customizing the columns showed in the <strong>Dive List</strong> panel</h4>
<div class="paragraph"><p>Grouping into trips allows a rapid way of accessing individual dives without
having to scan a long lists of dives. To group the dives in a dive list,
(from the Main Menu) select <em>Log → Autogroup</em>. The <strong>Dive List</strong> panel
now shows only the titles for the trips.</p></div>
<div class="sect3">
<h4 id="_editing_the_title_and_associated_information_for_a_particular_trip">7.3.1. Editing the title and associated information for a particular trip</h4>
<div class="paragraph"><p>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 <strong>Dive List</strong>. This shows a <strong>Trip Notes</strong> tab in the <strong>Notes</strong> panel. Here
you 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 used, the general weather and surface conditions during the trip, etc.).
After entering this
information, select <strong>Save</strong> from the buttons at the top right
of the <strong>Trip Notes</strong>
tab. The trip title in the <strong>Dive List</strong> panel should now reflect the
edited information.</p></div>
</div>
<div class="sect3">
<h4 id="_viewing_the_dives_during_a_particular_trip">7.3.2. Viewing the dives during a particular trip</h4>
<div class="paragraph"><p>Once the dives have been grouped into trips, you can expand one or more
trips by clicking the arrow-head on the left of each trip title. This expands
the selected trip, revealing individual dives done during the trip.</p></div>
</div>
<div class="sect3">
<h4 id="_collapsing_or_expanding_dive_information_for_different_trips">7.3.3. Collapsing or expanding dive information for different trips</h4>
<div class="paragraph"><p>After selecting a particular trip in the dive list, the
context menu allows several options to expand or collapse dives
within trips. This includes expanding all trips and collapsing all trips.</p></div>
</div>
<div class="sect3">
<h4 id="_merging_dives_from_more_than_one_trip_into_a_single_trip">7.3.4. Merging dives from more than one trip into a single trip</h4>
<div class="paragraph"><p>After selecting a trip title, the context menu allows the merging
of trips by either merging the selected trip with the trip below or with the
trip above. (Merge trip with trip below; Merge trip with trip above)</p></div>
</div>
<div class="sect3">
<h4 id="_splitting_a_single_trip_into_more_than_one_trip">7.3.5. Splitting a single trip into more than one trip</h4>
<div class="paragraph"><p>If a trip includes ten dives, you can split this trip into two trips (trip 1:
top 4 dives; trip 2: bottom 6 dives) by selecting and right-clicking the top
four dives. The resulting context menu lets the user create a new trip by
choosing the option <strong>Create new trip above</strong>. The top four dives are then
grouped
into a separate trip. The figures below show the selection and context menu
<div class="paragraph"><p>From the <em>Subsurface</em> window it’s easy to determine whether <em>Subsurface</em> has a valid connection to <em>Facebook</em>
From the <strong>Main Menu</strong>, select <em>Share on → Facebook</em> (image <strong>A</strong>, below). Normally, the <em>Facebook</em> option is greyed out. But
if there is a connection to <em>Facebook</em>, this option is active (i.e. in black color and can be selected).</p></div>
<div class="paragraph"><p>Having established a login to <em>Facebook</em>, transferring a dive profileto a <em>Facebook</em> timeline is easy.
Be sure the dive to be transferred to the timeline is shown in the <em>Subsurface</em> <strong>Dive Profile</strong> panel. If, from the <strong>Main Menu</strong>, you
select <em>Share on → Facebook</em> (see image <strong>A</strong> below), a dialogue box is shown, determining the amount of additional information transferred along
with the dive profile (image <strong>B</strong>, below). To transfer a dive profile to <em>Facebook</em>, the name of a
<em>Facebook</em> album is needed. The checkboxes on the left hand side let you decide how much
additional information should be transferred with the dive profile. This information is shown in the text box
on the right hand side of the panel (image <strong>B</strong>, below). You can easily edit the message that will be posted
with the dive profile. After specifying the additional information and verifying the text, select
the <em>OK</em> button that triggers the transfer to <em>Facebook</em>. After the transfer
is done, an acknowledgement dialogue appears, indicating it was successful.</p></div>
<div class="paragraph"><p>Both the album created and the post to your timeline will be marked as
private. In order for friends to be able to see it,
change its permissions from a regular Facebook login either in a
<div class="paragraph"><p>If required, then close the <em>Facebook</em> connection by either closing <em>Subsurface</em> or by selecting <em>File → Preferences → Facebook</em> from
the Main Menu, and clicking the appropriate button on the Facebook Preferences panel.</p></div>
</div>
<div class="sect2">
<h3 id="S_Export_other">8.2. Export dive information to other destinations or formats</h3>
<div class="paragraph"><p>For non-<em>Facebook exports</em>, the export function can be found by selecting <em>File → Export</em>, which brings up
the Export dialog. This dialog always gives two options: save ALL dives, or save only
the dives selected in <strong>Dive List</strong> panel of <em>Subsurface</em>. Click the appropriate
<img src="images/print2_f22.jpg" alt="FIGURE: Print one dive / page" />
</div>
</div>
<div class="ulist"><ul>
<li>
<p>
<em>Two Dives</em>: Print two dives per page, also showing the dive profiles.
</p>
</li>
<li>
<p>
<em>Six Dives</em>: Print six dives per page, also showing the dive profiles.
</p>
</li>
</ul></div>
<div class="paragraph"><p>You can <em>Preview</em> the printed page by selecting the <em>Preview</em> button on the
dialogue (see image <strong>A</strong> at the start of this section). After preview, you can change
the options in the print dialogue, so the layout fits personal taste.</p></div>
<div class="paragraph"><p>Next, select the <em>Print</em> button (see image <strong>A</strong> at the start of this section). This activates the regular print
dialogue used by the operating system,
letting you choose a printer and set its properties (see image below):</p></div>
<h3 id="_writing_a_custom_print_template_advanced">10.1. Writing a custom print template (advanced)</h3>
<div class="paragraph"><p>Writing a custom template is an effective way to produce highly customized printouts. Subsurface uses HTML templates
to render printing. You can create a template, export a new template, import an existing template and delete an existing template by using
the appropriate buttons under the <em>Template</em> dropdown list in the print dialogue. See <a href="#S_APPENDIX_E">APPENDIX E</a> for information on how
to write or modify a template.</p></div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="S_Configure">11. Configuring a dive computer</h2>
<div class="sectionbody">
<div class="paragraph"><p><em>Subsurface</em> lets you configure a dive computer. Currently the Heinrichs-Weikamp (OSTC 2, OSTC 3) and
Cobra, Gekko and Zoop) family of dive computers are supported. A large number of settings of these dive computers
can be read and changed to different values. To begin, be sure the appropriate hardware driver
is installed for the dive computer (also required for downloading dives) and the device name of the dive computer is known.
See <a href="#_appendix_a_operating_system_specific_information_for_importing_dive _information_from_a_dive_computer">APPENDIX A</a> for information on how to do this.</p></div>
<div class="paragraph"><p>Once the dive computer is connected to the <em>Subsurface</em> computer, select <em>File → Configure dive
computer</em> from the <em>Main Menu</em>. Provide the appropriate device name in the text box at the
top of the configuration panel and select the appropriate dive
computer model from the panel on the left-hand (see image below).</p></div>
<div class="paragraph" id="S_GradientFactors"><p>This panel allows two type of selections:</p></div>
<div class="ulist"><ul>
<li>
<p>
<strong>Show</strong>: Here you can specify the amount of information shown as part of
the dive profile:
</p>
<div class="ulist"><ul>
<li>
<p>
Thresholds: <em>Subsurface</em> can display the nitrogen, oxygen and the helium partial pressures during
the dive, done by using the toolbar on the left hand side of the <strong>Dive Profile</strong>
panel. For each of these graphs you can specify a threshold value on the right-hand side of the
Preferences panel. If any of the graphs go above the specified threshold level, the graph is
highlighted in red, indicating the particular partial pressure threshold has been exceeded.
</p>
</li>
<li>
<p>
_Max pO<sub>2</sub> is used for calculating the MOD when displaying the maximum operative depth (MOD)
for a dive. Specify an appropriate partial pressure. A value of 1.4 is commonly used.
</p>
</li>
<li>
<p>
<em>Draw dive computer reported ceiling red</em>: This checkbox does exactly what it says. By default
the computer reported ceiling is shown in white.
Not all dive computers report ceiling values. If the dive computer does report it, it may differ
from the ceilings calculated by <em>Subsurface</em> because of the different algorithms and
gradient factors, as well as the dynamic way a
dive computer calculates ceilings during a dive.
</p>
</li>
<li>
<p>
<em>Show unused cylinders in Equipment Tab</em>: This checkbox allows display of information about unused cylinders when viewing the
<strong>Equipment Tab</strong>. If this box is not checked, and if any cylinders entered using the <strong>Equipment Tab</strong> are not used (e.g. there
was no gas switch to such a cylinder), then these cylinders are omitted from that list.
</p>
</li>
<li>
<p>
<em>Show average depth</em>: If this box is checked, the <strong>Dive Profile</strong> panel contains a grey line that shows
the mean depth of the dive, up to any time instant during the dive. Normally this is a u-shaped line indicating the deepest mean depth just before
ascent.
</p>
</li>
</ul></div>
</li>
<li>
<p>
<strong>Misc</strong>:
</p>
<div class="ulist" id="GradientFactors_Ref"><ul>
<li>
<p>
Gradient Factors (GFLow and GFHigh):* Set the <em>gradient factors</em> used while diving. GF_Low is
the gradient factor at depth 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 nitrogen exposure during a dive, in a
similar way that many dive computers have a conservative 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 20/60 are considered conservative and values of 70/90 are considered
harsh. Checking the <strong>GFLow at max depth</strong> box causes GF_Low to be used at the
deepest depth of a dive. If this box is not checked, GF_Low is applied at
all depths deeper than the first deco stop. For more information see:
</p>
<div class="ulist"><ul>
<li>
<p>
<a href="http://www.tek-dive.com/portal/upload/M-Values.pdf">Understanding M-values by Erik Baker, <em>Immersed</em> Vol. 3, No. 3.</a>
</p>
</li>
<li>
<p>
<a href="http://www.rebreatherworld.com/general-and-new-to-rebreather-articles/5037-gradient-factors-for-dummies.html">Gradient factors for dummies, by Kevin Watts</a>
</p>
</li>
</ul></div>
</li>
<li>
<p>
<em>CCR: Show setpoints when viewing pO2:</em> With this checkbox activated, the pO<sub>2</sub>
graph on the dive profile has an overlay in red which indicates the CCR setpoint
values. See the section on <a href="#S_CCR_dives">Closed Circuit Rebreather dives</a>.
</p>
</li>
<li>
<p>
<em>CCR: Show individual O<sub>2</sub> sensor values when viewing pO<sub>2</sub>:</em> Show the pO<sub>2</sub>
values associated with each of the individual oxygen sensors of a CCR system.
See the section on <a href="#S_CCR_dives">Closed Circuit Rebreather dives</a>.
</p>
</li>
</ul></div>
</li>
<li>
<p>
<strong>Configuring dive planning using rebreather equipment:</strong>
</p>
<div class="ulist"><ul>
<li>
<p>
<em>Default CCR setpoint for dive planning:</em> Specify the O<sub>2</sub> setpoint for a
CCR dive plan. This determines the pO<sub>2</sub> maintained
during a particular dive. Setpoint changes during the dive can be added via the
profile context menu.
</p>
</li>
<li>
<p>
<em>pSCR O<sub>2</sub> metabolism rate:</em> For a semi-closed rebreather (pSCR) system, this is the
volume of oxygen used by a diver during a minute. Set this value for pSCR dive planning
and decompression calculations.
</p>
</li>
<li>
<p>
<em>pSCR ratio:</em> For pSCR equipment the dump ratio is the ratio of gas released to the
environment to that of the gas recirculated to the diver. Set this value for a
pSCR dive plan. A 1:10 ratio is commonly used.
</p>
</li>
</ul></div>
</li>
</ul></div>
</div>
<div class="sect2">
<h3 id="_language">12.4. Language</h3>
<div class="paragraph"><p>Choose a language that <em>Subsurface</em> will use.</p></div>
<img src="images/Pref4_f20.jpg" alt="FIGURE: Preferences Language page" />
</div>
</div>
<div class="paragraph"><p>A checkbox lets you use the <em>System Default</em> language which in most cases
will be the correct setting; with this <em>Subsurface</em> simply runs in the same
language / country settings as the underlying operating system.
To change it, uncheck this checkbox and pick a language / country
combination from the list of locations. The <em>Filter</em> text box
lists similar languages. For instance there are several system variants of English
or French. <strong>This particular preference requires a restart of <em>Subsurface</em> to take
effect</strong>.</p></div>
</div>
<div class="sect2">
<h3 id="_network">12.5. Network</h3>
<div class="paragraph"><p>This panel facilitates communication between <em>Subsurface</em> and data sources on the Internet.
This is important, for instance, when <em>Subsurface</em> needs to communicate with web
services such as Cloud storage or the <a href="#S_Companion"><em>Subsurface Companion app</em></a>. These Internet requirements are determined by your type of
connection to the Internet and by the Internet Service Provider (ISP) used.
Your ISP should provide the appropriate information.</p></div>
<td class="content">The <em>Subsurface</em> dive planner IS CURRENTLY EXPERIMENTAL
and assumes the user is already familiar with the <em>Subsurface</em>
user interface. It is explicitly used under the following conditions:</td>
</tr></table>
</div>
<div class="ulist"><ul>
<li>
<p>
The user is conversant with dive planning and has the necessary training to perform
dive planning.
</p>
</li>
<li>
<p>
The user plans dives within his/her certification limits.
</p>
</li>
<li>
<p>
Dive planning makes large assumptions about the characteristics of the <em>average person</em>
and cannot compensate for individual physiology or health or personal history or
life style characteristics.
</p>
</li>
<li>
<p>
The safety of a dive plan depends heavily on the way in which the planner is used.
</p>
</li>
<li>
<p>
The user is familiar with the user interface of <em>Subsurface</em>.
</p>
</li>
<li>
<p>
A user who is not absolutely sure about any of the above requirements should not use
this feature.
</p>
</li>
</ul></div>
</div></div>
<div class="sect2">
<h3 id="_the_em_subsurface_em_dive_planner_screen">13.1. The <em>Subsurface</em> dive planner screen</h3>
<div class="paragraph"><p>Like the <em>Subsurface</em> dive log, the planner screen is divided into several sections (see image below). The <strong>setup</strong>
parameters for a dive are entered into the sections on the left hand side of the screen.
They are: Available Gases, Rates, Planning, Gas Options and Notes.</p></div>
<div class="paragraph"><p>At the top right hand is a green <strong>design panel</strong> on which the profile of the dive can be
manipulated directly by dragging and clicking as explained below. This feature makes the
<em>Subsurface</em> dive planner unique in ease of use.</p></div>
<div class="paragraph"><p>At the bottom right is a text panel with a heading of <em>Dive Plan Details</em>. This is where the details of
the dive plan are provided in a way that can easily be copied to other software. This is also where
any warning messages about the dive plan are printed.</p></div>
<img src="images/rec_diveplan.jpg" alt="FIGURE: A recreational dive plan: setup" />
</div>
</div>
</div>
<div class="sect3">
<h4 id="_non_recreational_open_circuit_dives_including_decompression">13.2.2. Non-recreational open circuit dives, including decompression</h4>
<div class="paragraph"><p>Non-recreational dive planning involves exceeding the no-deco limits and/or using multiple breathing gases.
These dives are planned in three stages:</p></div>
<div class="paragraph"><p><strong>a) Nitrogen management</strong>: This is done by specifying the rates for descent and ascent,
as well as the deco model (GFLow, GFHigh or Conservatism level) under the headings <em>Rates</em> and <em>Planning</em>
to the bottom left of the planning screen. Two deco models are supported the Bühlmann model and the VPM-B
model. Select one of the two models. When selecting the Bühlmann model, the gradient factors (GF_high and GF_low
need to be specified. Initially, the GFHigh and GFLow values in the <em>Preferences</em>
panel of <em>Subsurface</em> is used. If these are changed within the planner (see <em>Gas Options</em> within
the planner), the new values are
used without changing the original values in the <em>Preferences</em>.
Gradient Factor settings strongly affect the calculated ceilings and their depths.
A very low GFLow value brings on decompression stops early during the dive.
** For more information about Gradient factors, see the section on <a href="#S_GradientFactors">Gradient Factor Preference settings</a>.</p></div>
<div class="paragraph"><p>If the VPM-B model is selected, the Conservatism_level needs to be specified on a scale of 0 (least conservative) to 4 (most conservative).
This model tends to give deco stops at deeper levels than the Bühlmann model and often results in slightly shorter
dive durations than the Bühlmann model. When selecting one of these models, keep in mind they are NOT exact physiological models but
only mathematical models that appear to work in practice.</p></div>
<div class="paragraph"><p>For more information external to this manual see:</p></div>
<div class="ulist"><ul>
<li>
<p>
<a href="http://www.tek-dive.com/portal/upload/M-Values.pdf">Understanding M-values by Erik Baker, <em>Immersed</em> Vol. 3, No. 3.</a>
</p>
</li>
<li>
<p>
<a href="http://www.rebreatherworld.com/general-and-new-to-rebreather-articles/5037-gradient-factors-for-dummies.html">Gradient factors for dummies, by Kevin Watts</a>
</p>
</li>
<li>
<p>
<a href="http://www.amazon.com/Deco-Divers-Decompression-Theory-Physiology/dp/1905492073/ref=sr_1_1?s=books&ie=UTF8&qid=1403932320&sr=1-1&keywords=deco+for+divers"><em>Deco for Divers</em>, by Mark Powell (2008). Aquapress</a> Southend-on-Sea, UK. ISBN 10: 1-905492-07-3.
An excellent non-technical review that discusses both the Bühlmann deco model and the VPM-B model.
</p>
</li>
</ul></div>
<div class="paragraph"><p>The ascent rate is critical for nitrogen off-gassing at the end of the dive and is specified
for several depth ranges, using the average (or mean) depth as a yardstick. The mean depth
of the dive plan is shown by a light grey line on the dive profile. Ascent rates
at deeper levels are often in the range of 8-12 m/min, while ascent rates near the surface are
often in the range of 4-9 m/min. The descent rate is also specified. If the option <em>Drop to first depth</em>
is activated, the descent phase of the planned dive will be at the maximal descent rate specified
in the <em>Rates</em> section of the dive setup.</p></div>
<div class="paragraph"><p><strong>b) Oxygen management</strong>: In the <strong>Gas Options</strong> part of the dive specification, the maximum partial
pressure for oxygen needs to be specified for the
bottom part of the dive (<em>bottom po2</em>) as well as for the decompression part of the dive (<em>deco po2</em>).
The most commonly
used values are 1.4 bar for the bottom part of the dive and 1.6 bar for any decompression
stages. Normally, a partial pressure of 1.6 bar is not exceeded. PO2 settings and the depth at which switching to a gas takes place can also be edited in the
<em>Available Gases</em> dialog. Normally the planner decides on switching to a new gas when, during
ascent, the partial pressure of the new gas has increased to 1.6 bar.</p></div>
<div class="paragraph"><p><strong>c) Gas management</strong>: With open-circuit dives this is a primary
consideration. Divers need to keep within the limits of the amount of
gas within the dive
cylinder(s), allowing for an appropriate margin for a safe return to the surface, possibly
sharing with a buddy. Under the <em>Gas Options</em> heading, specify the best (but conservative) estimate
of your surface-equivalent air consumption (SAC, also termed RMV) in
liters/min (for the time being, only SI units are supported). Specify the SAC during the
bottom part of the dive (<em>bottom SAC</em>) as well as during the decompression or safety stops of the
dive (<em>deco SAC</em>). Values of 15-30 l/min are common. For good gas management, a guess
is not sufficient and you needs to
monitor gas consumption on a regular basis, dependent on different dive conditions and/or equipment.
The planner calculates the total volume of gas used during the dive and issues a warning
if you exceeds the total amount of gas available. Good practice demands that divers not dive to
the limit of the gas supply but that an appropriate reserve is kept
for unforeseen circumstances.
For technical diving, this reserve can be up to 66% of the total available gas.</p></div>
<div class="paragraph"><p>Now you can start the detailed time-depth planning of the dive. <em>Subsurface</em> offers an unique
graphical interface for doing planning. Themechanics are
similar to hand-entering a dive profile in the dive log part of <em>Subsurface</em>. Upon activating the
planner, a default dive of depth 15 m for 40 min is offered in the blue design surface to the top
right hand of the screen. The white dots (waypoints) on the
profile can be dragged with a mouse. Create more waypoints by double-clicking on the profile
line and ensuring the profile reflects the intended dive. Drag the waypoints to represent
the depth and duration of the dive. It is NOT necessary to specify the ascent part of the dive
since the planner calculates this, based on the settings that have been specified.
If any of the management limits (for nitrogen, oxygen or gas) are exceeded, the surface
above the dive profile changes from BLUE to RED.</p></div>
<div class="paragraph"><p>Each waypoint on the dive profile creates a <em>Dive Planner Point</em> in the table on the
left of the dive planner panel. Be sure the <em>Used Gas</em> value in each row
of that table corresponds to one of the gas mixtures specified in the <em>Available Gases</em> table.
Add new waypoints until the main features of the dive have been completed, e.g. the
bottom time segment and deep stops (if these are implemented). Leave the remaining
waypoints on the ascent to <em>Subsurface</em>. In most cases <em>Subsurface</em>
computes additional way points in order to fulfill decompression requirements for that
dive. A waypoint can be moved by selecting it and by using the arrow keys.
The waypoints listed in the <em>Dive Planner Points</em> dialogue can be edited by hand in
order to get a precise presentation of the dive plan. In fact, you can create the
whole dive profile by editing the <em>Dive Planner Points</em> dialog.</p></div>
<div class="paragraph"><p>Show any changes in gas cylinder used by indicating gas changes as explained
in the section <a href="#S_CreateProfile">hand-creating a dive profile</a>. These changes should
reflect the cylinders and gas compositions defined in the table with <em>Available Gases</em>.
If two or more gases are used, automatic gas switches will be suggested during the ascent to
the surface. These changes can be deleted by right-clicking the gas change and
manually creating a gas change by right-clicking on the appropriate
waypoint.</p></div>
<div class="paragraph"><p>A non-zero value in the "CC set point" column of the table of dive planner points
indicates a valid setpoint for oxygen partial pressure and that the segment
is dived using a closed circuit rebreather (CCR). If the last manually entered
segment is a CCR segment, the decompression phase is computed assuming the diver
uses a CCR with the specified set-point. If the last segment (however
short) is on open circuit (OC, indicated by a zero set-point) the
decompression is computed in OC mode. The planner only considers gas
changes in OC mode.</p></div>
<div class="paragraph"><p>Below is an example of a dive plan to 45m using EAN26, followed by an ascent using EAN50
and using the settings as described above.</p></div>
<div class="paragraph"><p>To plan a dive using a closed circuit rebreather, select the <em>CCR</em> option in the dropdown
list, circled in blue in the image below.</p></div>
<div class="paragraph"><p><strong>Available gases</strong>: In the <em>Available gases</em> table, enter the cylinder information for the
diluent cylinder and for any bail-out cylinders. Do NOT enter the information for the oxygen
cylinder since it is implied when the <em>CCR</em> dropdown selection is made.</p></div>
<div class="paragraph"><p><strong>Entering setpoints</strong>: Specify a default setpoint in the Preferences tab, by selecting <em>File → Preferences → Graph</em> from
the main menu. All user-entered segments in the <em>Dive planner points</em> table
use the default setpoint value. Then, different setpoints can be specified for dive segments
in the <em>Dive planner points</em> table. A zero setpoint
means the diver bails out to open circuit mode for that segment. Decompression is always calculated
using the setpoint of the last manually entered segment. So, to plan a bail out ascent for a
CCR dive, add a one-minute dive segment to the end with a setpoint value of 0. The decompression
algorithm does not switch deco-gases automatically while in CCR mode (i.e. when a positive setpoint is specified) but
this is calculated for bail out ascents.</p></div>
<div class="paragraph"><p>The dive profile for a CCR dive may look something like the image below.</p></div>
<img src="images/Planner_CCR1_f20.jpg" alt="FIGURE: Planning a CCR dive: setup" />
</div>
</div>
<div class="paragraph"><p>Note that, in the <em>Dive plan details</em>, the gas consumption for a CCR segment is not calculated,
so gas consumptions of 0 liters are the norm.</p></div>
</div>
<div class="sect2">
<h3 id="S_Replan">13.5. Modifying an existing dive plan</h3>
<div class="paragraph"><p>Normally, when a dive plan has been saved, it is accessible from the <strong>Dive List</strong>, like any
other dive log. Within the <strong>Dive List</strong> there is no way to change a saved dive plan.
To change a dive plan, select it on the <strong>Dive List</strong>. Then, in the main menu,
select <em>Log → Re-plan dive</em>. This will open the selected dive plan within the dive planner,
letting changes be made and saved as usual.</p></div>
<div class="paragraph"><p>In addition, there is the option "Save new". This keeps the original
planned dive and adds a (possibly modified) copy to the dive list. If
that copy is saved with the same start time as the original, the two
dives are considered two versions of the same dive and do not
influence other each during decompression calculation (see next section).</p></div>
</div>
<div class="sect2">
<h3 id="_planning_for_repetitive_dives">13.6. Planning for repetitive dives</h3>
<div class="paragraph"><p>Repetitive dives can easily be planned if the dates and start times of the
repetitive dive set
are specified appropriately in the top left-hand <em>Start Time</em> field. <em>Subsurface</em>
calculates the gas loading figures and the affect of the first dive is
evaluated on later dives.</p></div>
<div class="paragraph"><p>If you have just completed a long/deep dive and are planning
another dive, then highlight, in the <strong>Dive List</strong>, the dive that has just been done
then activate the planner. Depending on the start time of the planned dive,
the planner takes into account the gas loading during the completed dive
and plans accordingly.</p></div>
<div class="paragraph"><p>If only a few standard configurations are used (e.g. in GUE), then a template dive can
be created conforming to one of the configurations. If you want to plan a dive using
this configuration, highlight the template dive in the <strong>Dive List</strong> and activate the
planner: the planner takes into account the configuration in the highlighted dive.</p></div>
</div>
<div class="sect2">
<h3 id="_printing_the_dive_plan">13.7. Printing the dive plan</h3>
<div class="paragraph"><p>Selecting the <em>Print</em> button in the planner allows printing of the <em>Dive Plan Details</em>
for wet notes. You can also cut and paste the <em>Dive Plan Details</em> to
include in a text file or word processing document.</p></div>
<div class="paragraph"><p>Dive plans have many characteristics in common with dive logs (dive profile, dive notes, etc).
After a dive plan has been saved, the dive details and gas calculations are saved in
the <strong>Notes</strong> tab. While a dive plan is being designed, it can be printed using
the <em>Print</em> button in the dive planner. This prints the dive details and gas calculations
in the <em>Dive Plan Details</em> panel of the dive planner. However, after the plan has been saved, it is
represented in a way very similar to a dive log and the gas calculations cannot be
accessed in the same way as during the planning process. The only way to print the
dive plan is to use the <em>File → Print</em> function on the main menu in the
same way as for dive logs or by copy and paste to a word processor.</p></div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_description_of_the_subsurface_main_menu_items">14. Description of the Subsurface Main Menu items</h2>
<div class="sectionbody">
<div class="paragraph"><p>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.</p></div>
<div class="sect2">
<h3 id="_file">14.1. File</h3>
<div class="ulist"><ul>
<li>
<p>
<a href="#S_NewLogbook"><em>New Logbook</em></a> - Close the currently open dive logbook and
clear all dive information.
</p>
</li>
<li>
<p>
<em>Open logbook</em> - Open the file manager to select a dive
logbook to open.
</p>
</li>
<li>
<p>
<em>Open cloud storage</em> - Open the dive log previously saved in <a href="#S_Cloud_storage"><em>Cloud storage</em></a>.
</p>
</li>
<li>
<p>
<em>Save</em> - Save the dive logbook currently open.
</p>
</li>
<li>
<p>
<em>Save to cloud storage</em> - Save the current dive log to <a href="#S_Cloud_storage"><em>Cloud storage</em></a>.
</p>
</li>
<li>
<p>
<em>Save as</em> - Save the current logbook under a different file name.
</p>
</li>
<li>
<p>
<em>Close</em> - Close the dive logbook currently open.
</p>
</li>
<li>
<p>
<a href="#S_ExportLog"><em>Export</em></a> - Export the currently open dive logbook (or
the selected dives in the logbook) to one of several formats.
</p>
</li>
<li>
<p>
<a href="#S_PrintDivelog"><em>Print</em></a> - Print the currently open logbook.
</p>
</li>
<li>
<p>
<a href="#S_Preferences"><em>Preferences</em></a> - Set the <em>Subsurface</em> preferences.
</p>
</li>
<li>
<p>
<a href="#S_FindMovedImages"><em>Find moved images</em></a> - If photos taken during dives have been moved to
a different disk or directory, locate them and link them to the appropriate dives.
</p>
</li>
<li>
<p>
<a href="#S_Configure"><em>Configure dive computer</em></a> - Edit the configuration of a dive computer.
</p>
</li>
<li>
<p>
<em>Quit</em> - Quit <em>Subsurface</em>.
</p>
</li>
</ul></div>
</div>
<div class="sect2">
<h3 id="_import">14.2. Import</h3>
<div class="ulist"><ul>
<li>
<p>
<a href="#S_ImportDiveComputer"><em>Import from dive computer</em></a> - Import dive information
from a dive computer.
</p>
</li>
<li>
<p>
<a href="#Unified_import"><em>Import Log Files</em></a> - Import dive information from a file in
in a <em>Subsurface</em>-compatible format.
</p>
</li>
<li>
<p>
<a href="#S_Companion"><em>Import GPS data from Subsurface web service</em></a> - Load GPS
coordinates from the <em>Subsurface</em> mobile phone app.
</p>
</li>
<li>
<p>
<a href="#S_ImportingDivelogsDe"><em>Import from Divelogs.de</em></a> - Import dive information
from <em>www.Divelogs.de</em>.
</p>
</li>
</ul></div>
</div>
<div class="sect2">
<h3 id="_log">14.3. Log</h3>
<div class="ulist"><ul>
<li>
<p>
<a href="#S_EnterData"><em>Add Dive</em></a> - Manually add a new dive to the <strong>Dive List</strong> panel.
</p>
</li>
<li>
<p>
<em>Edit dive</em> - Edit a dive where the profile was entered by hand and not from a dive computer.
</p>
</li>
<li>
<p>
<a href="#S_DivePlanner"><em>Plan Dive</em></a> - Plan dives.
</p>
</li>
<li>
<p>
<a href="#S_Replan"><em>Edit dive in planner</em></a> - Edit a dive plan that has been saved into the <strong>Dive List</strong>.
</p>
</li>
<li>
<p>
<a href="#S_CopyComponents"><em>Copy dive components</em></a> - Copy information
from several fields of a dive log onto the clipboard.
</p>
</li>
<li>
<p>
<em>Paste dive components</em> - Paste, into the selected dives in the <strong>Dive List</strong>,
the information copied using the <em>Copy dive components</em> option.
</p>
</li>
<li>
<p>
<a href="#S_Renumber"><em>Renumber</em></a> - Renumber the dives listed in the <strong>Dive List</strong>
panel.
</p>
</li>
<li>
<p>
<a href="#S_Group"><em>Auto Group</em></a> - Group the dives in the <strong>Dive List</strong> panel into dive
trips.
</p>
</li>
<li>
<p>
<a href="#S_DeviceNames"><em>Edit Device Names</em></a> - Edit the names of dive computers to coordinate your logs.
</p>
</li>
<li>
<p>
<a href="#S_Filter"><em>Filter divelist</em></a> - Select only some dives, based on specific tags or dive criteria.
</p>
</li>
</ul></div>
</div>
<div class="sect2">
<h3 id="_view">14.4. View</h3>
<div class="ulist"><ul>
<li>
<p>
<a href="#S_ViewPanels"><em>All</em></a> - View the four main <em>Subsurface</em> panels
all at once.
</p>
</li>
<li>
<p>
<a href="#S_ViewPanels"><em>Dive List</em></a> - View only the <strong>Dive List</strong> panel.
</p>
</li>
<li>
<p>
<a href="#S_ViewPanels"><em>Profile</em></a> - View only the <strong>Dive Profile</strong> panel.
</p>
</li>
<li>
<p>
<a href="#S_ViewPanels"><em>Info</em></a> - View only the <strong>Notes</strong> panel.
</p>
</li>
<li>
<p>
<a href="#S_ViewPanels"><em>Globe</em></a> - View only the <strong>World Map</strong> panel.
</p>
</li>
<li>
<p>
<em>Yearly Statistics</em> - Display summary statistics about dives during this and past
years.
</p>
</li>
<li>
<p>
<em>Prev DC</em> - Switch to data from previous dive computer, if a single dive was logged from more than one.
</p>
</li>
<li>
<p>
<em>Next DC</em> - Switch to next dive computer.
</p>
</li>
<li>
<p>
<em>Full Screen</em> - Toggles Full Screen mode.
</p>
</li>
</ul></div>
</div>
<div class="sect2">
<h3 id="_share_on">14.5. Share on</h3>
<div class="ulist"><ul>
<li>
<p>
<a href="#S_Facebook"><em>Facebook</em></a> - Share the currently selected dive on your Facebook timeline.
</p>
</li>
</ul></div>
</div>
<div class="sect2">
<h3 id="_help">14.6. Help</h3>
<div class="ulist"><ul>
<li>
<p>
<em>About Subsurface</em> - Show a panel with the version number of <em>Subsurface</em> as
well as licensing information.
</p>
</li>
<li>
<p>
<em>Check for updates</em> - Find out whether a newer version of Subsurface is available
on the <a href="http://subsurface-divelog.org/"><em>Subsurface</em> web site</a>.
</p>
</li>
<li>
<p>
<a href="#S_UserSurvey"><em>User survey</em></a> - Help to make <em>Subsurface</em> even better by taking part in our user survey
or by completing another survey if your diving habits have changed.
</p>
</li>
<li>
<p>
<em>User manual</em> - Open a window showing this user manual.
</p>
</li>
</ul></div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_appendix_a_operating_system_specific_information_for_importing_dive_information_from_a_dive_computer">15. APPENDIX A: Operating system specific information for importing dive information from a dive computer.</h2>
<div class="sectionbody">
<div class="sect2">
<h3 id="_make_sure_that_the_os_has_the_required_drivers_installed">15.1. Make sure that the OS has the required drivers installed</h3>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="images/icons/drivers.jpg" alt="Note" />
</td>
<td class="content">The operating system of the desktop computer needs the appropriate drivers in
order to communicate with the dive computer, the way the dive
<div class="paragraph"><p>Check that the status now includes <code><em>UP</em>, <em>RUNNING</em> AND <em>AUTH</em></code>.</p></div>
<div class="paragraph"><p>If there are multiple controllers running, it’s easiest to off the unused controller(s). For example, for <code>hci1</code>:</p></div>
<div class="literalblock">
<div class="content">
<pre><code>sudo hciconfig hci1 down</code></pre>
</div></div>
<div class="paragraph"><p>Next step is to <em>trust</em> and <em>pair</em> the dive computer. On distros with Bluez 5, such as Fedora 22,
one can use a tool called <code>blutootctl</code>, which will bring up its own command prompt.</p></div>
<code><controller></code> is the Bluetooth controller, <code>hci0</code>.
</p>
</li>
<li>
<p>
<code><dev></code> is the RFCOMM device file, <code>rfcomm0</code>
</p>
</li>
<li>
<p>
<code><bdaddr></code> is the dive computer’s MAC address, <code>00:11:22:33:44:55</code>
</p>
</li>
<li>
<p>
<code>[channel]</code> is the dive computer’s Bluetooth channel we need to connect to.
</p>
</li>
</ul></div>
<div class="paragraph"><p>If one omits it, channel 1 is assumed. Based on a limited number of user reports,
the appropriate channel for the dive computer is probably:</p></div>
<div class="ulist"><ul>
<li>
<p>
<em>Shearwater Petrel 1</em>: channel 1
</p>
</li>
<li>
<p>
<em>Shearwater Petrel 2</em>: channel 5
</p>
</li>
<li>
<p>
<em>Shearwater Nerd</em>: channel 5
</p>
</li>
<li>
<p>
<em>Heinrichs-Weikamp OSTC Sport</em>: channel 1
</p>
</li>
</ul></div>
<div class="paragraph"><p>E.g. to connect a <em>Shearwater Petrel 2</em>, set the dive computer to upload mode and enter:</p></div>
<div class="literalblock">
<div class="content">
<pre><code>sudo rfcomm -i hci0 connect rfcomm0 00:11:22:33:44:55 5 (enter a password, probably 0000, when prompted)</code></pre>
</div></div>
<div class="paragraph"><p>This gives the response:</p></div>
<div class="literalblock">
<div class="content">
<pre><code>Connected /dev/rfcomm0 to 00:11:22:33:44:55 on channel 5
Press CTRL-C for hangup</code></pre>
</div></div>
<div class="paragraph"><p>To connect a _Shearwater Petrel 1+ or + HW OSTC Sport+, set the dive computer to upload mode and enter:</p></div>
<div class="literalblock">
<div class="content">
<pre><code>sudo rfcomm -i hci0 connect rfcomm0 00:11:22:33:44:55 (enter a password, probably 0000, when prompted)
Connected /dev/rfcomm0 to 00:11:22:33:44:55 on channel 1
Press CTRL-C for hangup</code></pre>
</div></div>
<div class="paragraph"><p>If the specific channel the dive computer needs is not known, or the channel in the list above doesn’t
work, the command <code>sdptool records</code> should help determine the appropriate channel. The output
below is for a <em>Shearwater Petrel 2</em>.</p></div>
<div class="literalblock">
<div class="content">
<pre><code>sdptool -i hci0 records 00:11:22:33:44:55
Service Name: Serial Port
Service RecHandle: 0x10000
Service Class ID List:
"Serial Port" (0x1101)
Protocol Descriptor List:
"L2CAP" (0x0100)
"RFCOMM" (0x0003)
Channel: 5</code></pre>
</div></div>
<div class="paragraph"><p>For a Bluetooth dive computer not in the list above, or if the channel listed is not correct, please
let the Subsurface developers know on the user forum or the developer mailing list <em>subsurface@subsurface-divelog.org</em>.</p></div>
</div>
<div class="sect4">
<h5 id="_download_the_dives_with_subsurface">Download the dives with Subsurface</h5>
<div class="paragraph"><p>After establishing the RFCOMM connection and while the dive computer’s upload mode countdown is still running, go to_Subsurface_, select <em>Import→Import from dive computer</em> and enter appropriate Vendor (e.g. <em>Shearwater</em>), Dive Computer (<em>Petrel</em>), Device or Mount Point (<em>/dev/rfcomm0</em>) and click <em>Download</em>.</p></div>
</div>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_appendix_b_dive_computer_specific_information_for_importing_dive_information">16. APPENDIX B: Dive Computer specific information for importing dive data.</h2>
<div class="sectionbody">
<div class="sect2">
<h3 id="S_ImportUemis">16.1. Importing from Uemis Zurich</h3>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="images/icons/iumis.jpg" alt="Note" />
</td>
<td class="content"><em>Subsurface</em> downloads the information
stored on the SDA (the built-in file system of the Uemis) including
information about dive spots and
equipment. Buddy information is not yet downloadable.
Things are very similar to a normal USB-connected dive computer
(the Uemis is one of those that recharge when connected to the USB port).
The main difference is that you don’t enter a
device name, but instead the location where the UEMISSDA file system is
mounted once connected to the dive computer. On Windows this is a drive letter (
often <em>E:</em> or <em>F:</em>), on a Mac this is
<em>/Volumes/UEMISSDA</em> and on Linux systems this differs depending on the
distribution. On Fedora it usually is
<em>/var/run/media/<your_username>/UEMISSDA</em>. In all cases <em>Subsurface</em>
should suggest the correct location in the drop down list.</td>
</tr></table>
</div>
<div class="paragraph"><p>After selecting the above device name, download the
dives from the Uemis Zurich. One technical issue with the Uemis Zurich
download implementation (this is a Uemis firmware limitation, not a
<em>Subsurface</em> issue) is that you 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 you download 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 <em>Subsurface</em> displays an error
that the dive computer ran out of space, the solution is straightforward.
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. You
may have to do this more than once, depending on how many dives are
stored on the dive computer.</p></div>
</div>
<div class="sect2">
<h3 id="S_ImportingGalileo">16.2. Importing from Uwatec Galileo</h3>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="images/icons/Galileo.jpg" alt="Note" />
</td>
<td class="content">The Uwatec Galileo dive computers use infra red (IrDA) communication
between the dive computer and Subsurface. The Uwatec hardware uses
a USB dongle based on the serial infra-red (SIR) protocol and the
MSC7780 IrDA controller manufactured by MosChip
and marketed by Scubapro and some electronics companies.
Under Linux, the kernel
already provides for communication using the IrDA protocol. However,
the user additionally needs to load a driver for the IrDA interface
with the dive computer. The easiest way is to load the <strong>irda-tools</strong>
package from the <a href="http://irda.sourceforge.net/docs/startirda.html">Linux IrDA Project</a>.
After the installation of the irda-tools, the <strong>root user</strong> can specify a device name
from the console as follows:
<code>irattach irda0</code></td>
</tr></table>
</div>
<div class="paragraph"><p>After executing this command, Subsurface will recognize the Galileo
dive computer and download dive information.</p></div>
<div class="paragraph"><p>Under Windows, a similar situation exists. Drivers for the MCS7780 are
<td class="content">Specific instructions for downloading dives using Bluetooth are given in the section above, <a href="#S_Bluetooth"><em>Connecting Subsurface to a Bluetooth-enabled dive computer</em></a>.</td>
</tr></table>
</div>
</div>
<div class="sect2">
<h3 id="S_PoseidonMkVI">16.6. Importing from Poseidon MkVI Discovery</h3>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="images/MkVI.jpeg" alt="Note" />
</td>
<td class="content">Download of dive logs from the MkVI is performed using a custom communications
adapter and the <em>Poseidon PC Configuration Software</em>, obtained when purchasing
the MKVI equipment. The latter is a Windows application allowing configuration
of equipment and storage of dive logs. Communication between dive computer and
desktop computer utilizes the IrDA infra-red protocol. Only data for one dive
can be downloaded at a time, in three files:</td>
</tr></table>
</div>
<div class="ulist"><ul>
<li>
<p>
Setup configuration for the dive and key dive parameters (file with a .txt
extension)
</p>
</li>
<li>
<p>
Dive log details (file with a .csv extension)
</p>
</li>
<li>
<p>
Redbook format dive log (file with .cvsr extension). This is a compressed
version of the dive log using a proprietary format.
</p>
</li>
</ul></div>
<div class="paragraph"><p><em>Subsurface</em> accesses the .txt and the .csv files to get dive log information.</p></div>
</div>
<div class="sect2">
<h3 id="_importing_from_apd_inspiration_evolution_ccr">16.7. Importing from APD Inspiration/Evolution CCR</h3>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="images/APDComputer.jpg" alt="Note" />
</td>
<td class="content">The dive logs of an APD Inspiration or similar CCR dive computer are downloaded using
a communications adapter and <em>AP Communicator</em>, obtained when
purchasing the equipment. The dive logs can be viewed using the <em>AP Log Viewer</em>,
within Windows or Mac/OS. However, APD logs can be viewed and managed from within
<em>Subsurface</em> (together with dives using many other types of dive computer). The
APD inspiration dive logs are imported into <em>Subsurface</em> as follows:</td>
</tr></table>
</div>
<div class="ulist"><ul>
<li>
<p>
Download the dive using <em>AP Communicator</em>.
</p>
</li>
<li>
<p>
Open a dive within the <em>AP Log Viewer</em>.
</p>
</li>
<li>
<p>
Select the tab at the top of the screen, entitled "<em>Data</em>".
</p>
</li>
<li>
<p>
With the raw dive log data show on the screen, click on "<em>Copy to Clipboard</em>".
</p>
</li>
<li>
<p>
Open a text editor, e.g. Notepad (Windows) or TextWrangler (Mac).
</p>
</li>
<li>
<p>
Copy the contents of the clipboard into the text editor and save the text file
with a filename extension of <em>.apd</em>
</p>
</li>
<li>
<p>
Within <em>Subsurface</em>, select <em>Import → Import log files</em> to open the <a href="#Unified_import">universal import dialogue</a>.
</p>
</li>
<li>
<p>
In the dropdown list towards the bottom right of the dialogue (labeled <em>Filter:</em>), select "APD log viewer".
</p>
</li>
<li>
<p>
On the list of file names select the <em>.apd</em> file created. An import
dialogue opens showing the default settings for the data in the
<em>.apd</em> file. If changes are required,
do this as for <a href="#S_ImportingCSVDives">CSV imports</a>.
<td class="content">The best way to bring your logs from DivingLog to Subsurface is to
convert the whole database. This is because other export formats do not
include all the details, and would lack, for example, gas switches and
information of what units are used. With database import, all this
information is included and readily available.</td>
</tr></table>
</div>
<div class="paragraph"><p>To transfer all files from DivingLog to Subsurface:</p></div>
<div class="olist arabic"><ol class="arabic">
<li>
<p>
In DivingLog open the <em>File → Export → SQLite</em> menu
</p>
</li>
<li>
<p>
Select <em>Settings</em> button
</p>
</li>
<li>
<p>
Set the <em>RTF2Plaintext</em> to <em>true</em>
</p>
</li>
<li>
<p>
Close the Settings dialog
</p>
</li>
<li>
<p>
Click <em>Export</em> button and select the filename
</p>
</li>
</ol></div>
<div class="paragraph"><p>Once this is done, open the saved database file with Subsurface and the
dives are automatically converted to Subsurface’s own format. Last step to do is
save the log file in Subsurface.</p></div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_appendix_d_exporting_a_spreadsheet_to_csv_format">18. APPENDIX D: Exporting a spreadsheet to CSV format</h2>
<div class="sectionbody">
<div class="paragraph" id="S_Appendix_D"><p>Many divers keep a dive log in some form of digital file, commonly a spreadsheet
with various fields of information. These logs can be easily imported into <em>Subsurface</em> after the
spreadsheet is converted in a .CSV file.
This section explains the procedure to convert a diving logbook stored in a spreadsheet
to a .CSV file that will later be imported to <em>Subsurface</em>.
Creating a .CSV is straightforward, although the procedure is somewhat different
according to which spreadsheet program is used.</p></div>
<div class="paragraph"><p>Organize the diving data in the spreadsheet, so the first row
contains the names (or titles) of each column and the information for each dive is stored in a single row.
<em>Subsurface</em> supports many data items (Dive number, Date,
Time, Duration, Location, GPS, Max Depth, Mean Depth, Buddy, Notes, Weight and Tags).
Organize dive data following a few simple rules:</p></div>
<div class="olist arabic"><ol class="arabic">
<li>
<p>
Date: use one of the following formats: yyyy-mm-dd, dd.mm.yyyy, mm/dd/yyyy
</p>
</li>
<li>
<p>
Duration: the format should be minutes:seconds.
</p>
</li>
<li>
<p>
Unit system: only one unit system should be used (no mix of imperial and metric units)
</p>
</li>
<li>
<p>
Tags and buddies: values should be separated using a comma.
</p>
</li>
<li>
<p>
GPS position: use decimal degrees, e.g. 30.22496 30.821798
=== <em>LibreOffice Calc</em> and <em>OpenOffice Calc</em>
</p>
</li>
</ol></div>
<div class="paragraph"><p>These are open source spreadsheet applications forming parts of larger open source office suite applications. The user interaction with <em>LibreOffice</em> and <em>OpenOffice</em> is very similar.
In Libreoffice Calc the time format should be set to minutes:seconds - [mm]:ss and dates should be set to one of: yyyy-mm-dd, dd.mm.yyyy, mm/dd/yyyy. A typical dive log may look like this:</p></div>
<div class="paragraph"><p>To export the data as a .CSV file from within LibreOffice click <em>File → Save As</em>. On the dialogue that comes up, select the <em>Text CSV (.csv)</em> as the file type and select the option <em>Edit filter settings</em>.</p></div>
<img src="images/LOffice_save_as_options.jpg" alt="FIGURE: Save as options" />
</div>
</div>
<div class="paragraph"><p>After selecting <em>Save</em>, select the appropriate field delimiter (choose <em>Tab</em> to prevent conflicts with the comma when using this as a decimal point), then select <em>OK</em>.</p></div>
<img src="images/LOffice_field_options.jpg" alt="FIGURE: Field options" />
</div>
</div>
<div class="paragraph"><p>Double check the .CSV file by opening it with a text editor, and then import the dive data as explained on the section <a href="#S_ImportingCSVDives">Importing CSV dives</a>.</p></div>
<div class="sect2">
<h3 id="_microsoft_em_excel_em">18.1. Microsoft <em>Excel</em></h3>
<div class="paragraph"><p>The field delimiter (called "<em>list separator</em>" in Microsoft manuals) is not accessible
from within <em>Excel</em> and needs to be set through the <em>Microsoft Control Panel</em>. After changing the
separator character, all software on the Windows machine uses the new character as a separator.
You can change the character back to the default character by following the same procedure, outlined below.</p></div>
<div class="ulist"><ul>
<li>
<p>
In Microsoft Windows, click the <strong>Start</strong> button, then select <em>Control Panel</em> from the list on the right-hand side.
</p>
</li>
<li>
<p>
Open the <em>Regional and Language Options</em> dialog box.
</p>
</li>
<li>
<p>
Do one of the following:
</p>
<div class="ulist"><ul>
<li>
<p>
In Windows 7, click the <em>Formats</em> tab, and then click <em>Customize this format</em>.
</p>
</li>
<li>
<p>
In Windows XP, click the <em>Regional Options</em> tab, and then click <em>Customize</em>.
</p>
</li>
</ul></div>
</li>
<li>
<p>
Type a new separator in the <em>List separator</em> box. To use a TAB-delimited file, type the word TAB in the box.
</p>
</li>
<li>
<p>
Click <em>OK</em> twice.
</p>
</li>
</ul></div>
<div class="paragraph"><p>Below is an image of the <em>Control Panel</em>:</p></div>
<img src="images/Win_SaveCSV2.jpg" alt="FIGURE: Win List separator" />
</div>
</div>
<div class="paragraph"><p>To export the dive log in CSV format:</p></div>
<div class="paragraph"><p>With the dive log opened in <em>Excel</em>, select the round Windows button at the top left, then <em>Save As</em>.</p></div>
<img src="images/Win_SaveCSV1.jpg" alt="FIGURE: Excel save as option" />
</div>
</div>
<div class="paragraph"><p>Click on the left-hand part of the <em>Save as</em> option, NOT on the arrow on the right-hand. This brings up a dialogue for saving the
spreadsheet in an alternative format. From the dropdown list at the
bottom of the dialogue, marked <em>Save as Type:</em>, select <em>CSV(Comma delimited) (*.CSV)</em>. Be sure the appropriate folder has been
<div class="paragraph"><p>1) The <em>Style</em> tab (image <strong>A</strong> above) controls the font, line spacing and color template used for printing the dive log.
The style attributes are editable. Choose one of the four color palettes used for color printing.</p></div>
<div class="paragraph"><p>2) The <em>Colors</em> tab (image <strong>B</strong> above) allows editing the colors used for printing the dive log. The colors are highly
customizable: the <em>Edit</em> buttons in the <em>Colors</em> tab allows choosing arbitrary colors for different
components of the dive log printout.</p></div>
<div class="paragraph"><p>3) The <em>Template</em> tab of the Edit Panel (see image below) allows creating a template using HTML as well as a few
Grantlee programming primitives. Grantlee can create and format HTML code in
a highly simple but efficient way (see below). The HTML of the template can be edited and saved. The saved
template is stored in the same directory as the dive being processed. By default, a <em>Custom</em>
template is a skeleton with no specific print instructions. The information printed
needs to be specified and formatted in the template by replacing the section marked with:
"<!-- Template must be filled -→". Writing HTML code with Grantlee instructions allows unlimited
freedom in determining what is printed and in which way it should be rendered.</p></div>
<div class="paragraph"><p>You can adapt any of the existing templates and save it to the dive log directory. The standard templates (e.g. One dive, Six dives,
Table) can be modified in this way. After completing the edits, use the <em>Export</em> button in the print
dialogue to save the new template using a new template name.</p></div>
<div class="paragraph"><p>To write a custom template, the following elements must exist so the template will be correctly handled and rendered.</p></div>
<div class="sect2">
<h3 id="_main_dive_loop">19.1. Main dive loop</h3>
<div class="paragraph"><p><em>Subsurface</em> exports a dive list called (<strong>dives</strong>) to the <em>Grantlee</em> back end. It is possible to iterate over the list as follows:
.template.html</p></div>
<div class="literalblock">
<div class="content">
<pre><code> {% for dive in dives %}
<h1> {{ dive.number }} </h1>
{% endfor %}</code></pre>
</div></div>
<div class="literalblock">
<div class="title">output.html</div>
<div class="content">
<pre><code> <h1> 1 </h1>
<h1> 2 </h1>
<h1> 3 </h1></code></pre>
</div></div>
<div class="paragraph"><p>Additional information about <em>Grantlee</em> can be found at <a href="http://www.grantlee.org/apidox/for_themers.html">here</a></p></div>
<td align="left" valign="top"><p class="table">(<strong>string</strong>) OTU value for the dive</p></td>
</tr>
</tbody>
</table>
</div>
<div class="paragraph"><p><em>Subsurface</em> also exports <strong>template_options</strong> data. This data must be used as <em>CSS</em> values to provide a dynamically
editable template. The exported data is shown in the following table:</p></div>
<td align="left" valign="top"><p class="table">(<strong>int</strong>) border-width value dynamically calculated as 0.1% of the page width with minimum value of 1px</p></td>
<div class="paragraph"><p>Another variable that <em>Subsurface</em> exports is <strong>print_options</strong>. This variable contains a single member:</p></div>
<td align="left" valign="top"><p class="table">Use <em>CSS</em> filters to convert the page into grayscale (should be added to body style to enable printing grayscale prints)</p></td>
</tr>
</tbody>
</table>
</div>
<div class="literalblock">
<div class="title">template.html</div>
<div class="content">
<pre><code> body {
{{ print_options.grayscale }};
}</code></pre>
</div></div>
<div class="literalblock">
<div class="title">output.html</div>
<div class="content">
<pre><code> body {
-webkit-filter: grayscale(100%);
}</code></pre>
</div></div>
</div>
<div class="sect2">
<h3 id="_defined_css_selectors">19.3. Defined CSS selectors</h3>
<div class="paragraph"><p>As the dive profile is placed after rendering, <em>Subsurface</em> uses special <em>CSS</em> selectors to searche
in the HTML output. The <em>CSS</em> selectors in the following table should be added.</p></div>
<td align="left" valign="top"><p class="table">each dive that will contain a dive profile should have this class selector in addition to the dive_{{ dive.id }} id selector</p></td>
<h3 id="S_APPENDIX_F">20.1. Subsurface appears to miscalculate gas consumption and SAC</h3>
<div class="paragraph" id="SAC_CALCULATION"><p><em>Question</em>: I dived with a 12.2 l tank, starting with 220 bar and ending with 100 bar, and I calculate a different SAC compared what <em>Subsurface</em> calculates. Is <em>Subsurface</em>
miscalculating?</p></div>
<div class="paragraph"><p><em>Answer</em>: Not really. What happens is that <em>Subsurface</em> 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:
<code>consumption = tank size x (start pressure - end pressure)</code></p></div>
<div class="paragraph"><p>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 <strong>real</strong> calculation is:</p></div>
<div class="paragraph"><p>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 litres more, so you really did use only about 1437 l of air at surface pressure.</p></div>
<div class="paragraph"><p>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.</p></div>
</div>
<div class="sect2">
<h3 id="_some_dive_profiles_have_time_discrepancies_with_the_recorded_samples_from_my_dive_computer_8230">20.2. Some dive profiles have time discrepancies with the recorded samples from my dive computer…</h3>
<div class="paragraph"><p><em>Subsurface</em> ends up ignoring surface time for many things (average depth, divetime, SAC, etc).
<em>Question</em>: Why do dive durations in my dive computer differ from that given by <em>Subsurface</em>?</p></div>
<div class="paragraph"><p><em>Answer</em>: 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”.</p></div>
</div>
<div class="sect2">
<h3 id="_some_dive_profiles_are_missing_from_the_download">20.3. Some dive profiles are missing from the download</h3>
<div class="paragraph" id="DC_HISTORY"><p><em>Question</em>: I cannot download all my dives, only the most recent ones,
even though my dive computer’s manual states that it records history of
e.g. 999 dives?
<em>Answer</em>: Dive history is different than the dive profiles on the log.
The history only keeps track of the total number of dives and total
amount of time spent below surface. The logs, on the other hand, store
the dive profile, but they have a limited amount of memory to do so. The
exact amount of dive profiles that can be stored on the device depends on
sample interval and duration of the dives. Once the memory is full the
oldest dives get overwritten with new dives. Thus we are only able to
download the last 13, 30 or 199 dives.</p></div>
<div class="paragraph"><p>If you have downloaded your dives to different dive logging software
before they were overwritten, there is a good chance that Subsurface can
import these. However, if the logs are only on your dive computer, they
cannot be salvaged after being overwritten by new dives.</p></div>
