Documentation: update french translation of user-manual

Signed-off-by: Guillaume GARDET <guillaume.gardet@free.fr>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
This commit is contained in:
Guillaume GARDET 2015-09-08 10:38:20 +02:00 committed by Dirk Hohndel
parent a29f897125
commit 33831162f1
4 changed files with 3143 additions and 2621 deletions

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@ -304,11 +304,10 @@ a *W*, e.g. W07°, or with a negative value, e.g. -7.34323.
Some keyboards don't have the degree sign (°). It can be replaced by a d Some keyboards don't have the degree sign (°). It can be replaced by a d
like that: N30d W20d. like that: N30d W20d.
Please note that GPS coordinates of a dive site are linked to the Location Note that GPS coordinates of a dive site are linked to the Location name -
name - so adding coordinates to dives that do not have a location so adding coordinates to dives that do not have a location description will
description will cause unexpected behaviour (Subsurface will think that all cause unexpected behaviour (Subsurface will think that all of these dives
of these dives have the same location and try to keep their GPS coordinates have the same location and try to keep their GPS coordinates the same).
the same).
*Dive mode*: This is a dropdown box allowing one to choose the type of dive *Dive mode*: This is a dropdown box allowing one to choose the type of dive
performed. The options are OC (Open Circuit, the default setting, meant for most recreational dives), performed. The options are OC (Open Circuit, the default setting, meant for most recreational dives),
@ -1856,15 +1855,16 @@ Closed system rebreathers use advanced technology to recirculate gas that
has been breathed while doing two things to maintain a breathable oxygen has been breathed while doing two things to maintain a breathable oxygen
concentration: concentration:
a) remove carbon dioxide from the gas that has been exhaled a) remove carbon dioxide from the gas that has been exhaled
regulate the oxygen concentration to remain within safe diving limits. regulate the oxygen concentration to remain within safe diving limits. The
Currently, within _Subsurface_, the Poseidon MkVI Discovery is the best CCR interface of _Subsurface_ is currently experimental and under active
supported CCR dive computer. The CCR interface of _Subsurface_ is currently development. Subsurface currently supports Poseidon MkVI and APD
experimental and under active development. In contrast to a conventional Discovery/Evolution dive computers. In contrast to a conventional
recreational dive computer, a CCR system computer does not allow the recreational dive computer, a CCR system computer does not allow the
download of a log containing multiple dives. Rather, each dive is stored download of a log containing multiple dives. Rather, each dive is stored
independently. This means that _Subsurface_ cannot download a dive log independently. This means that _Subsurface_ cannot download a dive log
directly from a CCR dive computer, but that it imports CCR dive logs in the directly from a CCR dive computer, but that it imports CCR dive logs in the
same way that it imports dive log data from other digital databases. same way that it imports dive log data from other digital databases: one
dive at a time.
===== Import a CCR dive ===== Import a CCR dive
@ -1873,14 +1873,14 @@ information from other digital sources]. From the main menu of _Subsurface_,
select _Import -> Import log files_ to bring up the select _Import -> Import log files_ to bring up the
xref:Unified_import[universal import dialogue]. As explained in that xref:Unified_import[universal import dialogue]. As explained in that
section, the bottom right hand of the import dialogue contains a dropdown section, the bottom right hand of the import dialogue contains a dropdown
list of appropriate devices that currently includes an option for (Poseidon) list (labled _Filter:_) of appropriate devices that currently
MkVI files (import for other CCR equipment is under active includes(Poseidon) MkVI or APD log viewer files (import for other CCR
development). Having selected the appropriate CCR format and the directory equipment is under active development). Having selected the appropriate CCR
where the original dive logs have been stored from the CCR dive computer, format and the directory where the original dive logs have been stored from
one can select a particular dive log file (in the case of the MkVI it is a the CCR dive computer, one can select a particular dive log file (in the
file with a .txt extension). After selecting the appropriate dive log, case of the MkVI it is a file with a .txt extension). After selecting the
activate the _Open_ button at the bottom right hand of the universal import appropriate dive log, activate the _Open_ button at the bottom right hand of
dialogue. the universal import dialogue. See the section below for
===== Displayed information for a CCR dive ===== Displayed information for a CCR dive
@ -1910,18 +1910,18 @@ The oxygen setpoint values as well as the readings from the individual
oxygen sensors can be shown. The display of additional CCR information is oxygen sensors can be shown. The display of additional CCR information is
turned on by checking the appropriate checkboxes in the _Preferences_ panel turned on by checking the appropriate checkboxes in the _Preferences_ panel
(accessible by selecting xref:S_CCR_options[_File -> Preferences -> (accessible by selecting xref:S_CCR_options[_File -> Preferences ->
Graph_]). This part of the _Preferences_ panel look like this, representing Graph_]). This part of the _Preferences_ panel is shown in the image below,
two checkboxes that modify the display of pO~2~ when the appropriate toolbar representing two checkboxes that modify the display of pO~2~ when the
button on the Dive Profile has been activated. appropriate toolbar button on the Dive Profile has been activated.
image::images/CCR_preferences_f20.jpg["FIGURE: CCR preferences panel", align="center"] image::images/CCR_preferences_f20.jpg["FIGURE: CCR preferences panel", align="center"]
Checking any of the check boxes allows the display of additional Checking any of these check boxes allows the display of additional
oxygen-related information whenever the pO~2~ toolbar button on the oxygen-related information whenever the pO~2~ toolbar button on the
_Profile_ panel is activated. The first checkbox allows the display of _Profile_ panel is activated. The first checkbox allows the display of
setpoint information. This is a red line superimposed on the green oxygen setpoint information. This is a red line superimposed on the green oxygen
partial pressure graph and allows a comparison of the mean measured oxygen partial pressure graph and allows a comparison of the mean measured oxygen
partial pressure and the setpoint values, as in the image below. partial pressure and the setpoint values, as shown below.
image::images/CCR_setpoint_f20.jpg["FIGURE: CCR setpoint and po2 graph", align="center"] image::images/CCR_setpoint_f20.jpg["FIGURE: CCR setpoint and po2 graph", align="center"]
@ -1957,14 +1957,32 @@ including an overlay of setpoint and oxygen sensor data, as well as the
cylinder pressure data. In this case there is good agreement from the cylinder pressure data. In this case there is good agreement from the
readings of the two oxygen sensors. readings of the two oxygen sensors.
image::images/CCR_dive_profile_f20.jpg["FIGURE: CCR dive profile", align="center"] image::images/CCR_dive_profile_f22.jpg["FIGURE: CCR dive profile", align="center"]
_Equipment-specific information_: Equipment-specific information gathered by _Equipment-specific information_: Equipment-specific information gathered by
_Subsurface_ is shown in the xref:S_ExtraDataTab[Extra data tab]. This may _Subsurface_ is shown in the xref:S_ExtraDataTab[Extra data tab]. This may
include setup information or metadata about the dive. include setup information or metadata about the dive.
The deco ceiling calculated by Subsurface is not very accurate because the
precise pressure of nitrogen in the loop can usually not be determined from
the dive log imported from the CCR equipment. Many CCR dive computers,
however, report an internally-calculated deco ceiling that is reported in
the dive log, reflecting a more accurate assessment. The display of this
ceiling is activated by clicking the appropriate button to the left of the
dive profile:
[icon="images/icons/cceiling.jpg"]
The default colour of the computer-generated deco ceiling is white. However,
this can be set to red by checking the appropriate check box after selecting
_File -> Preferences -> Graph_. Below is a dive profile indicating the dive
computer-generated deco ceiling:
image::images/CCR_dive_ceilingF22.jpg["FIGURE: CCR computer-generated deco ceiling", align="center"]
More equipment-specific information for downloading CCR dive logs for More equipment-specific information for downloading CCR dive logs for
Poseidon MkVI and APD equipment can be found in xref:S_PoseidonMkVI[Appendix Poseidon MkVI and APD equipment can be found in
xref:_appendix_b_dive_computer_specific_information_for_importing_dive_information[Appendix
B]. B].
== Obtaining more information about dives entered into the logbook == Obtaining more information about dives entered into the logbook
@ -2815,78 +2833,90 @@ same process could be used for the Cloud-based storage of dive logs.
[[S_PrintDivelog]] [[S_PrintDivelog]]
== Printing a dive log == Printing a dive log
_Subsurface_ provides a simple interface to print a whole dive log or only a few selected dives. _Subsurface_ provides a simple and flexible interface to print a whole dive log or only a few selected dives.
Pre-installed templates or a custom written template can be used to choose where the data will Pre-installed templates or a custom written template can be used to choose where the data are fitted into the page.
be fitted into the page.
Before printing, two decisions are required: Before printing, two decisions are required:
- Should the whole dive log be printed or only part of it? If only part of the - Should the whole dive log be printed or only part of it? If only part of the
dive log is required, then the user must select the required dives from the dive log is required, then select the required dives from the *Dive List*
*Dive List* panel. panel.
- What gas partial pressure information is required on the dive profile? Users - If the dive profiles needs printing, what gas partial pressure information
should select the appropriate toggle-buttons on the button bar to the left should be shown? Select the appropriate toggle-buttons on the button bar to
of the Dive Profile panel. the left of the *Dive Profile* panel.
Now the print options should be selected to match the user's needs. To do If _File -> Print_ is selected from the Main menu, the the dialogue below
this, user should select _File -> Print_ from the Main menu. The following (image *A*) appears. Three specifications are needed to achieve the desired
dialogue appears (see the image on the left [A], below). information and page layout:
image::images/PrintDiveLog.jpg["FIGURE: Print dialogue", align="center"] image::images/Print1_f22.jpg["FIGURE: Print dialogue", align="center"]
Under _Print type_ users need to select one of two options: 1. Under _Print type_ select one of two options:
- _Dive list_ print: print dives from the list with profiles and other - _Dive list print_: Print dives from the *Dive List* panel with profiles and
information. other information.
- _Statistics_ print: print yearly statistics of the dives. - _Statistics print_: Print yearly statistics of the dives.
Under _Print options_ users need to select: 2. Under _Print options_ select:
- Printing only the dives that have been selected from the dive list prior to - Printing only the dives selected from the dive list prior to activating the
activating the print dialogue, achieved by checking the box _Print only print dialogue by checking the box _Print only selected dives_. If this
selected dives_. check box is *not* checked all dives in the *Dive List* panel are printed.
- Printing in colour, achieved by checking the box with _Print in colour_. - Printing in colour, achieved by checking the box with _Print in colour_. If
this check box is not checked, printing is in monochrome (grey scale).
Under _Template_ users can select: Under _Template_ select a template to be used as the page layout. There are
several templates (see image *B*, above).
- A template to be used as the page layout. - _Table_: This prints a summary table of all dives selected (see below).
- _Delete_ a template from the template list image::images/Print_summarylist_f22.jpg["FIGURE: Print summary table", align="center"]
- _Import_ a new template to the template list
- _Export_ a template from the template list
- _Edit_ a template (choose colors, fonts, font-type)
When editing a template the following options are available: - _Flow layout_: Print the text associated with each diev without printing the
dive profiles
of each dive (see below):
- _Style_: edit font type, size, choose color palette; this will not affect image::images/Print_flow_layout_f22.jpg["FIGURE: Print flow layout", align="center"]
the template HTML code
- _Template_: edit the template HTML code; by saving, the "Custom" template in - _One Dive_: Print one dive per page, also showing the dive profile (see
the template list will be replaced below)
- _Colors_: edit the current color palette; the new color palette will
overwrite the "Custom" color palette image::images/print2_f22.jpg["FIGURE: Print one dive / page", align="center"]
- _Two Dives_: Print two dives per page, also showing the dive profiles.
- _Six Dives_: Print six dives per page, also showing the dive profiles.
- _Custom_: This option allows customisation of the print contents and
layout. This is
discussed at the end of this section.
Users can _Preview_ the printed page by selecting the _Preview_ button on Users can _Preview_ the printed page by selecting the _Preview_ button on
the dialogue. After preview, changes to the options in the print dialogue the dialogue (see image *A* at the start of this section). After preview,
can be made, resulting in a layout that fits personal taste. changes to the options in the print dialogue can be made, resulting in a
layout that fits personal taste.
Next, select the _Print_ button in the dialogue. This activates the regular Next, select the _Print_ button (see image *A* at the start of this
print dialogue used by the user operating system (image [*B*] in the middle, section). This activates the regular print dialogue used by the user
above), allowing them to choose a printer and to set its properties (image operating system, allowing one to choose a printer and to set its properties
[*C*] on the right, above). It is important to set the print resolution of (see image below):
the printer to an appropriate value by changing the printer
properties. Finally, one can print the dives. Below is a (rather small) image::images/Print_print_f22.jpg["FIGURE: Print one dive / page", align="center"]
example of the output for one particular page.
Set the print resolution of the printer to an appropriate value by changing
the printer _Properties_. Finally, select the _Print_ button to print the
dives. Below is a (rather small) example of the output for one particular
page.
image::images/Printpreview.jpg["FIGURE: Print preview page", align="center"] image::images/Printpreview.jpg["FIGURE: Print preview page", align="center"]
=== Write a custom printing template (advanced) === Write a custom printing template (advanced)
Writing a custom template is an effective way to produce highly customized Writing a custom template is an effective way to produce highly customized
printouts. Subsurface uses HTML templates with Grantlee as the printing printouts. Subsurface uses HTML templates to render printing. One can create
backend. a template, export a new template, import an existing template and delete an
existing template by using the appropriate buttons under the _Template_
See <<_appendix_f_write_a_custom_printing_template ,APPENDIX F>> for dropdown list in the print dialogue. See <<S_APPENDIX_E,APPENDIX E>> for
information on how to write your own template. information on how to write or modify a template.
[[S_Configure]] [[S_Configure]]
== Configurer un ordinateur de plongée == Configurer un ordinateur de plongée
@ -4058,7 +4088,7 @@ _Subsurface_ accesses the .txt and the .csv files to obtain dive log
information. information.
=== Importing from APD Inspiration CCR === Importing from APD Inspiration/Evolution CCR
[icon="images/APDComputer.jpg"] [icon="images/APDComputer.jpg"]
[NOTE] [NOTE]
@ -4070,25 +4100,39 @@ managed from within _Subsurface_ (together with dives using many other types
of dive computer). The APD inspiration dive logs are imported into of dive computer). The APD inspiration dive logs are imported into
_Subsurface_ as follows: _Subsurface_ as follows:
- Download the dive using _AP Communicator_.
- Open a dive within the _AP Log Viewer_. - Open a dive within the _AP Log Viewer_.
- Select the tab at the top of the screen, entitled "_Data_". - Select the tab at the top of the screen, entitled "_Data_".
- If the raw dive log data show on the screen, click on "_Copy to Clipboard_". - With the raw dive log data show on the screen, click on "_Copy to
- Open a text editor, e.g. Notepad (Windows), TextWrangler (Mac). Clipboard_".
- Open a text editor, e.g. Notepad (Windows) or TextWrangler (Mac).
- Copy the contents of the clipboard into the text editor and save the text - Copy the contents of the clipboard into the text editor and save the text
file with a filename extension of .CSV file with a filename extension of _.apd_
- Within _Subsurface_, select _Import -> Import log files_ to open the - Within _Subsurface_, select _Import -> Import log files_ to open the
xref:Unified_import[universal import dialogue]. xref:Unified_import[universal import dialogue].
- In the dropdown list towards the bottom right of the dialogue, select "_CSV - In the dropdown list towards the bottom right of the dialogue (labled
files_". 'Filter:'), select "APD log viewer".
- On the list of file names select the .CSV file that has been created - On the list of file names select the _.apd_ file that has been created
above. An import dialogue opens. above. An import dialogue opens indicating the default settings for the data
- In the dropdown list on the top left labeled '_Pre-configured imports_", in the _.apd_ file. If any changes are required, do this as for
select _APD Log Viewer_. xref:S_ImportingCSVDives[CSV imports].
- Ensure the other settings for the ADP dive log are appropriate, then select
_OK_.
The APD dive log will appear within _Subsurface_. image::images/APD_CSVimportF22.jpg["Figure: APD log viewer import", align="center"]
- The top left hand dropdown box in the import panel allows one to select the
APD dive computer for which the dive log needs to be imported. The default
it is DC1, _i.e._ the first of the two dive computers the APD uses. It is
possible to sequentially import the data for both dive computers by first
importing CD1 and then DC2.(*Hint*: The logs for the two dive computers are
viewed by selecting _View -> Next DC_ from the Main Menu after the uploading
has been completed)
- Click the _Ok_ button at the bottom of the import panel.
The APD dive log will appear within _Subsurface_. The dive
computer-generated ceiling generated by the Inspiration can be viewed by
selecting the appropriate button on the left of the *Dive Profile*. Cylinder
pressure data are not logged by the APD equipment but can be manually
entered in the _Equipment_ Tab.
== APPENDIX C: Exporting Dive log information from external dive log software. == APPENDIX C: Exporting Dive log information from external dive log software.
@ -4219,8 +4263,8 @@ Once this is done, open the saved database file with Subsurface and the
dives are automatically converted to our own format. Last step to do is save dives are automatically converted to our own format. Last step to do is save
the log file in Subsurface. the log file in Subsurface.
[[S_Appendix_D]]
== ANNEXE D : Exporter un tableur vers le format CSV == ANNEXE D : Exporter un tableur vers le format CSV
[[S_Appendix_D]]
De nombreux plongeurs conservent un carnet de plongée sous forme de fichier De nombreux plongeurs conservent un carnet de plongée sous forme de fichier
numérique, souvent un tableur avec différents champs et informations. Ces numérique, souvent un tableur avec différents champs et informations. Ces
@ -4318,92 +4362,55 @@ that was selected. One can double check the .CSV file by opening it with a
text editor, and then import the dive data as explained on the section text editor, and then import the dive data as explained on the section
xref:S_ImportingCSVDives[Importing CSV dives]. xref:S_ImportingCSVDives[Importing CSV dives].
== APPENDIX E: FAQs. [[S_APPENDIX_E]]
== ANNEXE E : Créer un modèle d'impression personnalisé
=== Subsurface appears to miscalculate gas consumption and SAC _Subsurface_ provides a mechanism to create or modify templates for printing
[[SAC_CALCULATION]] dive logs in order to produce customised printouts of dive logs. Templates,
'Question': I dived with a 12.2 l tank, starting with 220 bar and ending written in HTML as well as a simple Grantlee instruction set, are rendered
with 100 bar, and I calculate a different SAC compared what _Subsurface_ to the print device by _Subsurface_.
calculates. Is _Subsurface_ miscalculating?
'Answer': Not really. What happens is that _Subsurface_ actually calculates Templates are accessed using the print dialogue (see image *B* below).
gas consumption differently - and better - than you expect. In particular,
it takes the incompressibility of the gas into account. Traditionally, Gas
consumption and SAC should be: +consumption = tank size x (start pressure -
end pressure)+
and that's true for an ideal gas, and it's what you get taught in dive image::images/Print1_f22.jpg["FIGURE: Print dialogue", align="center"]
theory. But an "ideal gas" doesn't actually exist, and real gases actually
don't compress linearly with pressure. Also, you are missing the fact that
one atmosphere of pressure isn't actually one bar. So the *real*
calculation is:
+consumption = (amount_of_air_at_beginning - amount_of_air_at_end)+ The buttons under the _Template_ dropdown box allows one to _Edit_,
_Delete_, _Import_ and to _Export_ templates (see image *A* above). New or
modified templates are stored as HTML files in the same directory as the
dive log being processed. In order to create or modify a template, select
the _Custom_ template from the template dropdown list in the print dialogue
(see image *B* above), then select _Edit_.
where the amount of air is *not* just "tank size times pressure in bar". The Edit Panel comprises three tabs:
It's a combination of: "take compressibility into account" (which is a
fairly small issue under 220 bar - you'll see more differences when you do
high-pressure tanks with 300bar) and "convert bar to atm" (which is the
majority of your discrepancy). Remember: one ATM is ~1.013 bar, so without
the compressibility, your gas use is:
+12.2*((220-100)/1.013)+ image::images/Template1_f22.jpg["FIGURE: template edit dialogue", align="center"]
which is about 1445, not 1464. So there was 19 l too much in your simple 1) The _Style_ tab (image *A* above) controls the font, line spacing and colour
calculation that ignored the difference between 1 bar and one ATM. The template used for printing the dive log. The style attributes are
compressibility does show up above 200 bar, and takes that 1445 down about editable. Choose one of the four colour palets used for colour printing.
eight litres more, so you really did use only about 1437 l of air at surface
pressure.
So be happy: your SAC really is better than your calculations indicated. Or 2) The _Colors_ tab (image *B* above) allows editing the colours used for
be sad: your cylinder contains less air than you thought it did. And as printing the dive log. The colours are highly customisable: the _Edit_
mentioned, the "contains less air than you thought it did" really starts buttons in the _Colors_ tab allows choosing abritrary colours for different
becoming much more noticeable at high pressure. A 400 bar really does not components of the dive log printout.
contain twice as much air as a 200 bar one. At lower pressures, air acts
pretty much like an ideal gas.
=== Some dive profiles have time discrepancies with the recorded samples from my dive computer... 3) The _Template_ tab of the Edit Panel (see image below) allows creating a
template using HTML as well as a few Grantlee programming
primitives. Grantlee provides the ability to 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 _Custom_ template is a skeleton with
no specific print instructions. The informastion being printed needs to be
specified and formatted in the by replacing the section marked with: "<!--
Template must be filled -->". Writing HTML code with Grantlee instructions
allows unlimited freedom in determining what is printed an in which way it
should be rendered.
_Subsurface_ ends up ignoring surface time for many things (average depth, image::images/Template2_f22.jpg["FIGURE:Template tab", align="center"]
divetime, SAC, etc). 'Question': Why do dive durations in my dive computer
differ from that given by _Subsurface_?
'Answer': For example, if you end up doing a weight check (deep enough to One can adapt any of the existing templates and save it to the dive log
trigger the "dive started") but then come back up and wait five minutes for directory. The standard templates (e.g. One dive, Six dives, Table) can be
your buddies, your dive computer may say that your dive is 50 minutes long - modified in this way.
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”.
=== Some dive profiles are missing from the download
[[DC_HISTORY]]
'Question': 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.
'Answer': 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 limited amount of memory to do so. The exact amount
of dive profiles that can be stored on the device depend 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.
If you have downloaded your dives to different dive logging software before
they were overwritten, there is a high change that Subsurface can import
these. However, if the logs are only on your dive computer, they cannot be
salvaged after being over written by new dives.
== APPENDIX F: Write a custom printing template
_Subsurface_ provides a customizable printing support which is based on
templates that are transformed by the _Grantlee_ backend to correct _HTML_
syntax, The _HTML_ output is then rendered by _Subsurface_.
To write a custom template the following elements must exist so that the To write a custom template the following elements must exist so that the
template will be correctly handled and rendered. template will be correctly handled and rendered.
@ -4540,3 +4547,84 @@ rendering mode
IMPORTANT: All CSS units should be in relative lengths only, to support printing on any IMPORTANT: All CSS units should be in relative lengths only, to support printing on any
page size. page size.
== APPENDIX F: FAQs.
[[S_APPENDIX_F]]
=== Subsurface appears to miscalculate gas consumption and SAC
[[SAC_CALCULATION]]
'Question': 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 _Subsurface_
calculates. Is _Subsurface_ miscalculating?
'Answer': Not really. What happens is that _Subsurface_ actually calculates
gas consumption differently - and better - than you expect. In particular,
it takes the incompressibility of the gas into account. Traditionally, Gas
consumption and SAC should be: +consumption = tank size x (start pressure -
end pressure)+
and that's true for an ideal gas, and it's what you get taught in dive
theory. But an "ideal gas" doesn't actually exist, and real gases actually
don't compress linearly with pressure. Also, you are missing the fact that
one atmosphere of pressure isn't actually one bar. So the *real*
calculation is:
+consumption = (amount_of_air_at_beginning - amount_of_air_at_end)+
where the amount of air is *not* just "tank size times pressure in bar".
It's a combination of: "take compressibility into account" (which is a
fairly small issue under 220 bar - you'll see more differences when you do
high-pressure tanks with 300bar) and "convert bar to atm" (which is the
majority of your discrepancy). Remember: one ATM is ~1.013 bar, so without
the compressibility, your gas use is:
+12.2*((220-100)/1.013)+
which is about 1445, not 1464. So there was 19 l too much in your simple
calculation that ignored the difference between 1 bar and one ATM. The
compressibility does show up above 200 bar, and takes that 1445 down about
eight litres more, so you really did use only about 1437 l of air at surface
pressure.
So be happy: your SAC really is better than your calculations indicated. Or
be sad: your cylinder contains less air than you thought it did. And as
mentioned, the "contains less air than you thought it did" really starts
becoming much more noticeable at high pressure. A 400 bar really does not
contain twice as much air as a 200 bar one. At lower pressures, air acts
pretty much like an ideal gas.
=== Some dive profiles have time discrepancies with the recorded samples from my dive computer...
_Subsurface_ ends up ignoring surface time for many things (average depth,
divetime, SAC, etc). 'Question': Why do dive durations in my dive computer
differ from that given by _Subsurface_?
'Answer': 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”.
=== Some dive profiles are missing from the download
[[DC_HISTORY]]
'Question': 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.
'Answer': 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 limited amount of memory to do so. The exact amount
of dive profiles that can be stored on the device depend 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.
If you have downloaded your dives to different dive logging software before
they were overwritten, there is a high change that Subsurface can import
these. However, if the logs are only on your dive computer, they cannot be
salvaged after being over written by new dives.