Contents

1 Introduction

The LeseSolm package provides some AWK [5] and shell scripts for usage with the GPS Logger “Solmeta Geotagger Pro” [2]. This device is a direct geotagger with magnetic compass for certain Nikon SLR cameras. In addition, it logs the GPS track in its internal memory in plain NMEA format [8].

LeseSolm downloads the track log from the Geotagger and writes the NMEA data into a file. Also, you can query the memory usage and erase the logger memory.

GeotagSolm reads the NMEA file and geotags the images that have been taken while the Geotagger was on the camera hot shoe. The image direction from the magnetic compass is saved into the images, too. The universal meta data tool ExifTool by Phil Harvey [3] is used for writing the GPS data into image files or XMP sidecar files, respectively.

GeotagNMEA does the same as GeotagSolm, but it can be used with arbitrary GPS tracks in NMEA format. Above a certain speed threshold, the image direction is inferred from the GPS track direction.

For image files with GPS coordinates RevGeotag retrieves the corresponding altitude values from the web service of geonames.org [4], which can be used for updating the altitudes in the images.

StatNMEA analyses NMEA GPS track files with respect to DOP values, satellite information, speed distribution and other properties.

BackupExif makes backups of the EXIF meta data from image files.

CreateXMP creates simple XMP sidecar files to be geotagged instead of the original image files.

License

The LeseSolm package is licensed under the GNU General Public License version 2 as defined in the file COPYING or at www.gnu.org/licenses/. All parts of the LeseSolm package come without any warranty. Use at your own risk.

Synopsis

LeseSolm.awk [COMPORT]

GeotagSolm.awk NMEA TIME IMAGEFILES

GeotagNMEA.awk NMEA TIME IMAGEFILES

RevGeotag.awk a/b/c IMAGEFILES

StatNMEA.awk NMEA

BackupEXIF.sh IMAGEFILES

CreateXMP.sh IMAGEFILES

NMEA: GPS track log file in NMEA format. TIME = (camera time) - (GPS time), e.g. +2:0:7.

2 Installation

This section describes the installation of LeseSolm under Linux. The procedure should be similar for other Unix-like environments. ExifTool [3] and GAWK [5] must be installed on your system. All the files LeseSolm.awk, GeotagSolm.awk,... from the archive LeseSolm-0.x.y.zip can be placed in any directory.¹ Open a terminal there and make the scripts executable by

chmod +x *.awk *.sh

on the command line. If that directory is in the PATH environment variable, you can start the scripts anywhere just by LeseSolm.awk, GeotagSolm.awk, etc. Otherwise you have to write the full path. E.g. if LeseSolm is in the current directory it can be started by "./LeseSolm.awk". In the following we assume that the directory with the scripts is in PATH.

If you receive error messages about “gawk” not being found, you should check where the “gawk” executable is by typing “whereis gawk” on the command line. Change the first line in the AWK scripts accordingly. Finally, it is necessary to use GNU AWK (GAWK) [5] because other AWK implementations may not work. In Ubuntu 10.10 only MAWK is installed by default, thus you have to install GAWK using the package manager.

2.1 Configuration file “.LeseSolm”

Several scripts in the LeseSolm package read out the configuration file “.LeseSolm” if it exists in your home directory. The settings therein will not be overwritten when you update LeseSolm to a newer version. An example file “dot.LeseSolm” is part of the package. Adjust the settings therein, move it to your home directory and rename it to “.LeseSolm”. Avoid blanks in setting lines!

2.2 LeseSolm under Windows

LeseSolm can be used under Windows² in a Cygwin environment. Here are the step-by-step instructions for the installation. First download setup.exe from the Cygwin webpage [6]. Run setup.exe and follow the instruction until you arrive at the package selection. There you select the packages All⊳Perl⊳perl, All⊳Devel⊳make, All⊳ Shells⊳chere and All⊳Archive⊳unzip by clicking on the symbols with the two round arrows. Continue and finish the installation. Start a bash shell from the Windows Start menu (Start⊳ Programs⊳Cygwin⊳Cygwin Bash Shell). Download Image-ExifTool-...tar.gz (not the Windows executable) from [3] and LeseSolm-...zip from [1]. Save both files into the directory “c:\Program Files\cygwin\home\user\” where “user” is your windows user name and “Program Files” may be called differently depending on the Windows language and version. Go back to the Cygwin shell window and type the following lines, where “...” denotes the version number.

chere -i

tar -xzvf Image-ExifTool-...tar.gz

cd Image-ExifTool-...

perl Makefile.PL

make test

make install

cd ~

unzip LeseSolm-...zip

cd LeseSolm-...

chmod +x *.awk *.sh

cp *.awk *.sh /usr/local/bin/

cp dot.LeseSolm ~/.LeseSolm

Now everything should be ready for using LeseSolm under Windows. In the Windows explorer there is a new entry “Bash Prompt Here” in the context menu when you right-click on a folder. It opens a Cygwin shell in that folder, where you can use the LeseSolm scripts as explained in this manual.

These instructions have been tested under Windows XP with cygwin-1.7.9, exiftool-8.60 and LeseSolm-0.0.13.

3 LeseSolm

LeseSolm downloads the GPS track log from the “Solmeta Geotagger Pro”.

3.1 Usage

Connect the Geotagger to an USB port, open a terminal and change to the directory where the track log shall be saved. Turn the logger on and start LeseSolm by

LeseSolm.awk COMPORT

You may replace COMPORT by the serial interface file to the logger. If COMPORT is omitted LeseSolm tries to detect the correct interface automatically. If this fails the default value of COMPORT is "/dev/ttyUSB0". You need read and write permissions to the serial interface file. In Opensuse 11.3 it is sufficient to be member of the group dialout. Ubuntu 10.10 users should first read Sec. 3.2 below.

LeseSolm will show you a menu:

>LeseSolm 0.0.5: Auslesewerkzeug für den Solmeta Geotagger Pro

>Leseprozeß mit PID 9438 gestartet, öffne Schnittstelle /dev/ttyUSB0, 4800

>Befehl: Version (v), Download (d), Löschen (erase), Ende (q), Abbrechen (abort)

Type "v" (plus ENTER) for showing the version (#Ver) and the used memory (#mem) of the Geotagger.

>Version anzeigen, 4800

>#Ver: Solmeta PRO V1.0-4 (Dec 03 2009)

>#mem:48KB

If nothing is shown try it again. Sometimes the Geotagger ignors commands.

The command "d" downloads the track log from the Geotagger and saves the data into the file Solmeta_YYYY-MM-DD-HHMMSS.nmea, where YYYY-... denotes the date and UTC time of the first track point. Wait until the download is complete.

>Auslesen

>#connect

>Sende #down, 115200

>#download00c2

>Lese Zeile 907, 48/ 48 KiB, 100%.

>#downcomplete

>907 Zeilen gelesen in 0:10 min, 4.8 KiB/s.

>14 GPGGA Sätze gefunden.

>NMEA Daten nach Solmeta_2011-02-15-190933.nmea geschrieben.

>Umschalten auf 4800

In this example 907 lines have been saved into the file Solmeta_2011-02-15-190933.nmea. Among them are 14 $GPGGA sentences. For the old version 10.0 of the Geotagger, each $GPGGA sentence corresponds to one photo if the Geotagger was operational and mounted on the hot shoe of the camera.

Now check the NMEA file for completeness. If everything is OK, you can erase the Geotagger memory by typing "erase". Wait approximately one minute until the process is finished.

>Logger leeren, 4800

>#StartErase

>Löschen läuft, bitte warten.

>#erasecomplete

>Logger geleert nach 41 s.

"v" will show you that the Geotagger is empty now.

>Version anzeigen, 4800

>#Ver: Solmeta PRO V1.0-4 (Dec 03 2009)

>#mem:0KB

Type "q" to quit. Turn the logger off.

3.2 Remarks

• You can abort the download and erase processes with "abort". This may confuse the Geotagger and you may have to turn it off. Use this option only when the Geotagger hangs.
• The LeseSolm script is experimental, it works fine for my configuration:
  Old hardware version (10.0) of the "Solmeta Geotagger Pro", Opensuse 11.3,
  gawk-3.1.6-31.1.i586, coreutils-7.1-11.1.1.i586.
• Using LeseSolm under Ubuntu 10.10: there is a bug, which leads to errors when accessing the serial interface [7]. A possible workaround is first unloading and reloading the cp210x kernel module:

  sudo modprobe -r cp210x

  sudo modprobe cp210x

  It seems that this bug was fixed in Ubuntu 11.04.

• For me LeseSolm works better than the Windoze tool, which often hangs. The USB-COM driver is already part of the Linux kernel. No need to install drivers. The NMEA files created by LeseSolm are given reasonable file names.
• The download command "d" does not overwrite existing “Solmeta_YYYY...SS.nmea“ files, instead the log is written into the file “Solmeta_YYYY-...SS-xxxx.nmea”, where xxxx is a number starting from 0001.

4 GeotagSolm

GeotagSolm enhances image files (or XMP sidecar files) with GPS data from the Geotagger. Be careful, geotagging is a delicate process because your image files will be modified.³ To be precise, it is the image meta data which will be amended by GPS data. It is strongly recommended that you keep your original files in a safe place. For the beginning, work only on copies in a separate directory. Instead of geotagging your image files you can write the GPS data also into XMP sidecar files and leave the images untouched. In addition, backups of the original EXIF data in the image files can be made. See Sec. 7 below for details. GeotagSolm needs ExifTool, which is available for Linux and many other operating systems. If you cannot find it in the repositories of your distribution, you can get it from the ExifTool homepage [3].

GeotagSolm is useful for geotagging photos taken by a camera with the Geotagger mounted on it. Therefore, the NMEA data file must come from the Geotagger.⁴ For photos taken with another camera and/or for using other NMEA data, the script GeotagNMEA can be used for geotagging, see Sec. 5.

4.1 Usage

1. Start the geotagging script by

   GeotagSolm.awk NMEA TIME IMAGEFILES

   Mandatory arguments:

   • NMEA denotes the track log file from the Geotagger.
   • TIME is the time shift between the camera time (EXIF:DateTimeOriginal) and GPS time (UTC), precisely: (Camera time) = (TIME + GPSTime) with a 10 second tolerance. The format for TIME is (±)H:M:S. If the hour (H), the minute (M) or the second (S) are omitted they are set to zero. Examples:

   +1 = +1:0:0, -1:13:3, ::4 = 0:0:4, -0:3 = -0:3:0.

   • For track logs from the old Geotagger (10.0), it is sufficient to specify TIME within the 10 second tolerance. However, logs from later versions (10.1, 10.2) require TIME to be set precisely within one second. Also, the log interval of the Geotagger should be set to 1 second for precise geotagging.
   • IMAGEFILES specifies the files and directories you want to geotag. Wildcards (*) will be expanded by the shell. Be careful, * means all files and all files in sub-directories. It is better to use something like *.JPG or *.xmp.

   Examples:

   GeotagSolm.awk Solmeta_2011-01-22.nmea +1::7 DSC_4766.JPG DSC_4773.JPG Folder

   This means that the camera time is assumed to be (GPSTime + 3607 sec). The files DSC_4766.JPG and DSC_4773.JPG will be geotagged as well as all suitable files in the directory Folder.

   GeotagSolm.awk Solmeta_2011-01-22.nmea +1::7 *.xmp

   Same action as above, but the GPS data is written into XMP sidecar files (*.xmp). If you do not have these files, you can create them from your JPG images with "CreateXMP.sh *.JPG". See Sec. 7.2 for details.

2. If GeotagSolm finds damaged sentences in the NMEA file, it shows the corresponding approximate line numbers:

   >==== Die NMEA Datei enthält 8 Fehler ungefähr bei den Zeilen:

   >42, 15281, 15356, 17419, 18879, 18882, 18885, 18888

   >

   >Fehler ignorieren (i) oder abbrechen (a)?

   In this example, 8 errors were found and the approximate line numbers are given. You have the option to ignore the errors by typing "i", or abort GeotagSolm with "a". If the NMEA file is from the old Geotagger version 10.0 you should abort and correct the errors in a text editor, otherwise some images may not be geotagged. Track logs from the version 10.1 or 10.2 Geotagger usually contain a large number of GPS positions and ignoring the errors is rather safe.

3. After GeotagSolm has related the image files (or XMP files) to the GPS positions, and before the image files are updated, it will present a menu:

   >Befehl: (geo)  Geodaten mit ExifTool in Bilder schreiben

   >        (list) Liste mit den zum Geotaggen vorgesehenen Bildern anzeigen

   >        (arg)  ExifTool Argumente-Datei anzeigen

   >        (quit) Abbruch, temporäre Dateien bleiben erhalten

   Type "list" to show which files are going to be geotagged. Check this list for errors. In the case that some images cannot be geotagged they will be shown first. You can exit the list view with "q", which gets you back to the GeotagSolm menu.

   "arg" shows the arguments to be passed over to ExifTool. Again you get back with "q".

   "quit" will quit without writing anything. Use this command if you found errors in the lists.

   After you have checked that everything is fine, type "geo" to let ExifTool write the geo data into the files. Watch out for error messages from ExifTool. Now check if the geotagged files and the meta data therein can be properly accessed by your image applications. Consult the ExifTool homepage [3] for compatibility issues.

4.2 Remarks

• GeotagSolm works quite comfortably with track logs from the old Geotagger version because it has the "universal geotagging" feature. This allows relating GPS positions to images very precisely without knowing the exact time difference. More recent Geotagger versions (10.1, 10.2) do not have this capability, but they can log in 1 second intervals. Consequently, if you know the exact difference between GPS time and image time, precise geotagging is possible, too.
• If the correlation of GPS time and image time fails, improve the value of the TIME argument. The relation

  must be true within the tolerance of 10 seconds. See below how to change the tolerance.

  It is a good idea to have the minutes and seconds of the camera clock synchronised with the GPS time before taking pictures. Then TIME is just the time zone designator, e.g. +1 in Central Europe (or +2 during summer time).

• The NMEA sentences in the track log must be time-ordered, oldest first. GeotagSolm will work faster if the image files are time-ordered, too.
• The following EXIF tags will be (over)written:

  GPS Version ID                  : 2.2.0.0

  GPS Latitude Ref                : North

  GPS Latitude                    : xx deg xx’ 16.82"

  GPS Longitude Ref               : East

  GPS Longitude                   : xx deg xx’ 5.00"

  GPS Altitude Ref                : Above Sea Level

  GPS Altitude                    : 350 m

  GPS Time Stamp                  : 13:19:22

  GPS Satellites                  : 11

  GPS Status                      : Measurement Active

  GPS Dilution Of Precision       : 0.8

  GPS Speed Ref                   : km/h

  GPS Speed                       : 0.1852

  GPS Track Ref                   : True North

  GPS Track                       : 72.39

  GPS Img Direction Ref           : Magnetic North

  GPS Img Direction               : 125.4

  GPS Map Datum                   : WGS-84

  GPS Processing Method           : GPS(D)

  GPS Date Stamp                  : 2010:12:08

  GPS Differential                : Differential Corrected

  User Comment                    : Blabla; H(125.4),P(3.6),R(-1.3)

  The original UserComment "Blabla" will be appended by the image direction (compass heading H), the pitch (P) and the roll (R) angles given in degrees. Spaces at the end of "UserComment" are removed.

  The tag "GPS Dilution Of Precision" is always HDOP because PDOP is not logged.

  Moreover, I have enhanced the tag "GPS Processing Method", it reads "GPS(x)", where x denotes the FAA mode indicator from the end of the $GPRMC sentence. x can be A (autonomous), D (differential), E (estimated), M (manual), N (not valid), S (simulated). A means normal, D differential corrected, and E indicates that the indoor function of the Geotagger was active.

• It can happen that an NMEA sentence in the track log is broken, which yields error/warning messages or simply wrong meta data entries. In this case you can try to repair the broken sentence by hand. Links to the specification are given in [8]. Then run GeotagSolm again using the repaired NMEA file.
• GeotagSolm can be adjusted easily by editing the config file “.LeseSolm”, see Sec. 2.1. There you can modify several parameters:

  ## ZeitTol

  ## EN: Time tolerance in seconds

  GeotagSolm.ZeitTol=10

  "ZeitTol" specifies the tolerance in seconds for matching GPS time with image time.

  ## interaktiv

  ## EN: 0: Geotagging without user interaction, 1: a menu will be shown

  GeotagSolm.interaktiv=1

  Set "interaktiv" to 0 to turn off the menu. Then GeotagSolm will not ask for confirmation before modifying the image files.

  ## ExiftoolPfad

  ## EN: Path to ExifTool executable

  GeotagSolm.ExiftoolPfad=exiftool

  If the "exiftool" executable is not in PATH, you can specify its exact location in "ExiftoolPfad".

  ## ExiftoolGeotagOpt

  ## EN: Additional ExifTool options. Each entry must end with "\n".

  GeotagSolm.ExiftoolGeotagOpt=-overwrite_original_in_place\n

  In "ExiftoolGeotagOpt" you can set additional ExifTool parameters. They must be formatted for the usage in an argument file. Consult the ExifTool documentation [3] for details. Since LeseSolm version 0.0.7 no "_original" backup files will be created any more, and the original image files will be overwritten. If you still want the backup files, remove the “-overwrite...\n” option.

5 GeotagNMEA

GeotagNMEA is a geotagging tool that works similarly to GeotagSolm, but it accepts arbitrary GPS track files in NMEA format. It is useful for geotagging photos from a camera, which was not connected to the Geotagger. Also, you can use track logs from a different GPS logger. The logs from the Geotagger are supported as well.

Before proceeding, please read Sec. 4. In the following, only the differences will be explained.

5.1 Usage

Start the geotagging script by

GeotagNMEA.awk NMEA TIME IMAGEFILES

Mandatory arguments:

• NMEA denotes the track log file in NMEA format, IMAGEFILES are the images to be geotagged. TIME is the time shift between the camera time (EXIF:DateTimeOriginal) and GPS (UTC) time, precisely: (Camera time) = (TIME + GPSTime) with a one hour tolerance by default. The tolerance value can be changed in the variable "GeotagNMEA.ZeitTol" as explained in Sec. 4.2.
• The format for TIME is (r∕g)(±)H:M:S. Hour (H), minute (M) and second (S) default to zero if omitted. Unlike GeotagSolm, here you can specify which is the first NMEA sentence in a set of sentences describing the same GPS position/time point. “r” means $GPRMC (default), and “g” $GPGGA, respectively. Examples:

  +1 = +1:0:0, g-1:13:3, r1:0:4

  Choosing this correctly is important for track logs with big time intervals (more than a second) between track points. For instance, choose r for version 10.0 of the Solmeta Geotagger Pro, and g for version 10.1 (and above?).
  If you do not know what is the default for your GPS logger, set the log interval to 10 seconds and take one minute of data (after a GPS fix!). Then look at the time (the field after the first comma) in the $GPGGA and $GPRMC sentences in the NMEA file. Find out which ($GPRMC+$GPGGA) pairs belong together. The sentence which comes first in this pair determines r∕g.

Note that in the “.LeseSolm” config file the settings have the prefix “GeotagNMEA” not “GeotagSolm”.

5.2 Image direction

By default, the magnetic compass information from the Geotagger (in the sentence $PTNTHPR) is not used by GeotagNMEA. You can turn it on with GeotagNMEA.UsePTN=1 in the LeseSolm config file. It makes no sense to use the magnetic compass if the Geotagger is not aligned with the camera. If it is properly aligned, use GeotagSolm.

GeotagNMEA determines the image direction from the GPS track ($GPRMC) if the velocity is above a certain threshold. This can be useful when taking pictures in the direction of movement, e.g. through the front screen of a car. The velocity threshold (in km/h) is set by the settings variable GeotagNMEA.MinvImgDir. The default is 6 km/h, set it to 999999 if you want to turn off this feature.

5.3 EXIF DOP

GeotagNMEA reads the $GPGSA sentence if present and writes the EXIF tag MeasureMode accordingly. “2” corresponds to a 2D GPS fix and the EXIF DOP tag is filled with the HDOP value. “3” corresponds to 3D GPS fix, and PDOP is used instead of HDOP. If $GPGSA is absent, EXIF DOP is filled with the HDOP value from $GPGGA.

6 RevGeotag

For image files with valid GPS coordinates RevGeotag fetches the corresponding altitude values from the geonames.org web service [4] and updates the EXIF tag “GPSAltitude”. Start the script with

RevGeotag.awk x IMAGESFILES

where IMAGEFILES denotes the images with coordinates. x must be replaced by a, b or c, which means the following. If x is a the script RevGeotag retrieves the altitude values only for images without “GPSAltitude” entry. In the mode b the altitude values are shown for all images, but only images without altitude will be updated. Finally, if x is c all images will be updated and existing “GPSAltitude” entries will be overwritten. Example:

RevGeotag.awk c *.JPG *.xmp

RevGeotag shows the same menu as GeotagSolm and GeotagNMEA. The command “list” displays the images together with the altitude values from geonames.org and the original altitudes if existent. It depends on the mode a/b/c whether the images will be updated or not. If there is an existing altitude entry its value altiold will be saved in the EXIF tag “GPSProcessingMethod” as ALT(altiold).⁵ Also the new value altinew will be saved there in the form DEM(xyz:altinew), where xyz denotes the digital elevation model (DEM). Example from the list view:

Bild 3: ./DSC_4467.JPG

Lat: +xx.xx2337°, Lon: +x.xx3281°

Höhe im Bild : +41.90 m

Neue Höhe    : +35.00 m, Diff = -6.90 m = -9.0% von (|alt|+|neu|)

GPS ProcessingMethod: GPS(A),ALT(41.9m),DEM(astergdem:35m)

Use the command “geo” for updating your images with the new values. Before that you can inspect the ExifTool argument file with “arg”. The command “quit” exits without doing anything.

Apart from the settings discussed in Sec. 4.2 you can adjust the following variables in the config file “.LeseSolm”, see also Sec. 2.1: Currently, geonames.org offers data from three DEMs: astergdem, srtm3 and gtopo30 [10]. The default is set in

RevGeotag.geonamesEleService=astergdem

To retrieve information from the geonames.org web service an account is needed. RevGeotag comes already with a free account, however, you can also use your own by changing

RevGeotag.geonamesUser=lesesolm

In this case, replace “lesesolm” in the last line by your geonames.org user name.⁶

Finally, you can specify an HTTP proxy and other things, which is documented in “.LeseSolm”.

7 Helper scripts

Two helper shell scripts have been added. They are useful shortcuts for ExifTool. The scripts can be adjusted easily to your needs. The script StatNMEA analyses NMEA files.

7.1 BackupEXIF

"BackupEXIF.sh IMAGEFILES" makes backups of the EXIF meta date in IMAGEFILES. The backup files have the file extension ".orig.exif" and they are placed into the hidden directory ".origexif". For instance, the following command creates the EXIF files foto.orig.exif and *.orig.exif:

BackupEXIF.sh foto.jpg *.JPG

If necessary, the EXIF data from "foto.orig.exif" can be written back to foto.jpg by

exiftool -P -tagsfromfile .origexif/foto.orig.exif -b -exif foto.jpg

If only GPS data tags and the UserComment shall be restored you can use

exiftool -P -tagsfromfile .origexif/foto.orig.exif -gps:all -UserComment foto.jpg

Consult the ExifTool homepage [3] for all possibilities.

Making backups of the EXIF meta data is a good idea in general before you modify your image files with whatever program or operating system function. There are certainly lots of applications which do not handle meta data with care. Even better is saving your images to a safe place immediately after they have been downloaded from your camera or memory card. However, this requires more disk space than the ".orig.exif" files.

7.2 CreateXMP

"CreateXMP.sh IMAGEFILES" creates simple XMP sidecar files for storing the GPS data therein instead of writing it into the image files. For example,

CreateXMP.sh *.JPG

produces the files "*.xmp" corresponding to the "*.JPG" files. After that, use

GeotagSolm.awk NMEA TIME *.xmp

to store the GPS data in the XMP sidecar files. Here, the original JPG files are left untouched.

Of course, for this procedure to be useful, your image applications should be capable of using XMP sidecar files. If your images come already with XMP sidecar files, you do not need to create them with CreateXMP, just run GeotagSolm or GeotagNMEA on them.

7.3 StatNMEA

For number freaks and fans of statistics StatNMEA provides a simple analysis of GPS track logs in NMEA format. Start it with

StatNMEA.awk NMEA

where NMEA denotes one or more NMEA data files.

The following information is shown, where MMM denotes “mean (mit), maximal (max) and minimal (min)”. In the distribution for a variable x, [a,b) means a ≤ x < b.

1. Abundance of some NMEA sentences.
2. MMM value of the speed entry in $GPRMC, and the speed distribution.
3. Distribution and MMM values of HDOP from $GPGGA, HDOP, PDOP and VDOP from $GPGSA, and the number of satellites in view from $GPGGA.
4. Abundance of satellites used for the GPS fix (from $GPGSA). MMM of their signal to noise (S/N) ratios, minimal and maximal values of their elevation and azimuth (from $GPGSV).
5. As 4., but for all satellites in view as indicated in $GPGSV.
6. Abundances of
   1. GPS fix modes from $GPGSA. 1: no fix, 2/3: 2D/3D fix.
   2. FAA mode indicator from $GPRMC: A, D, E, ..., see Sec. 4.2.
   3. GPS quality indicator from $GPGGA: 0, 1, 2, ..., the values are related to the FAA indicator, see Ref. [8] for more information.

The amount of information shown depends on the completeness of the NMEA file. Detailed satellite data requires $GPGSA and $GPGSV. The NMEA satellite ID numbers are equal to the PRN numbers for ID ≤ 32. For ID > 32 the PRN number is (ID + 87). ID numbers greater 32 correspond to SBAS satellites (and others?).

7.3.1 Example 1: Solmeta Geotagger Pro 10.0

The Geotagger [2] does not log the $GPGSA and $GPGSV sentences. Therefore, the shown data is sparse.

StatNMEA 0.0.9

Lese Zeile   4788.

==== GPS Track enhält 4788 Zeilen.

Beginn: 2011:03:17 13:17:04.376

Ende:   2011:03:17 19:20:37.000

==== NMEA Sätze

GPRMC: 2243 = 100%

GPGGA: 132 = 5.88498%

PTNTHPR: 2262 = 100.847%

==== GPRMC speed (km/h)

RMC-Speed:  2243, mit =  2.25, max =  8.5, min =  0.0

Verteilung:

[  0,  2):  1245 = 55.5%

[  2,  7):   977 = 43.6%

[  7, 15):    21 =  0.9%

[ 15, 30):     0 =  0.0%

[ 30, 60):     0 =  0.0%

[ 60,120):     0 =  0.0%

[120,240):     0 =  0.0%

[240,500):     0 =  0.0%

[500,800):     0 =  0.0%

[800,inf):     0 =  0.0%

==== DOP Werte

GGA-HDOP:   132, mit =  1.35, max =  6.7, min =  0.8

GGA-Sats:   132, mit =  7.79, max =   11, min =    4

Verteilung:      ggaHDOP         gsaHDOP         gsaPDOP         gsaVDOP

[ 0, 1):      34 = 25.8%

[ 1, 2):      86 = 65.2%

[ 2, 3):       4 =  3.0%

[ 3, 4):       4 =  3.0%

[ 4, 5):       2 =  1.5%

[ 5, 6):       1 =  0.8%

[ 6, 7):       1 =  0.8%

[ 7, 8):       0 =  0.0%

[ 8, 9):       0 =  0.0%

[ 9,10):       0 =  0.0%

[10,11):       0 =  0.0%

==== Sats in use

==== Sats in view

==== GPS Fix Infos

RMC-FAA A:  1544 = 68.8%

RMC-FAA D:   689 = 30.7%

RMC-FAA E:     8 =  0.4%

GGA-FixQual 1:   113 = 85.6%

GGA-FixQual 2:    19 = 14.4%

7.3.2 Example 2: Locosys GPS Walker

This GPS Logger by Locosys [11] logs $GPGSA and $GPGSV sentences, and the corresponding data is shown.

StatNMEA 0.0.9

Lese Zeile  31713.

==== GPS Track enhält 31713 Zeilen.

Beginn: 2011:02:07 13:04:23.244

Ende:   2011:02:07 18:52:50.000

==== NMEA Sätze

GPRMC: 8810 = 100%

GPGGA: 8810 = 100%

GPGSA: 8810 = 100%

GPGSV: 5283 = 59.9659%

GPGSV Gruppen: 1761 = 19.9886%

==== GPRMC speed (km/h)

RMC-Speed:  8810, mit = 231.07, max = 865.3, min =  0.0

Verteilung:

[  0,  2):  2257 = 25.6%

[  2,  7):  2052 = 23.3%

[  7, 15):   286 =  3.2%

[ 15, 30):   290 =  3.3%

[ 30, 60):   835 =  9.5%

[ 60,120):   299 =  3.4%

[120,240):    38 =  0.4%

[240,500):   401 =  4.6%

[500,800):   834 =  9.5%

[800,inf):  1518 = 17.2%

==== DOP Werte

GGA-HDOP:  8777, mit =  2.41, max =  9.8, min =  0.8

GSA-HDOP:  8777, mit =  2.41, max =  9.8, min =  0.8

GSA-PDOP:  8777, mit =  3.80, max = 10.3, min =  1.4

GSA-VDOP:  8777, mit =  2.85, max =  9.1, min =  1.1

GGA-Sats:  8789, mit =  5.82, max =   10, min =    3

Verteilung:      ggaHDOP         gsaHDOP         gsaPDOP         gsaVDOP

[ 0, 1):      40 =  0.5%      40 =  0.5%       0 =  0.0%       0 =  0.0%

[ 1, 2):    4707 = 53.6%    4707 = 53.6%     562 =  6.4%    2316 = 26.4%

[ 2, 3):    1603 = 18.3%    1603 = 18.3%    3008 = 34.3%    2869 = 32.7%

[ 3, 4):     827 =  9.4%     827 =  9.4%    1788 = 20.4%    2564 = 29.2%

[ 4, 5):    1167 = 13.3%    1167 = 13.3%    1381 = 15.7%     411 =  4.7%

[ 5, 6):     307 =  3.5%     307 =  3.5%    1437 = 16.4%     252 =  2.9%

[ 6, 7):      20 =  0.2%      20 =  0.2%     116 =  1.3%      58 =  0.7%

[ 7, 8):      79 =  0.9%      79 =  0.9%      41 =  0.5%     183 =  2.1%

[ 8, 9):      25 =  0.3%      25 =  0.3%     131 =  1.5%     121 =  1.4%

[ 9,10):       2 =  0.0%       2 =  0.0%     312 =  3.6%       3 =  0.0%

[10,11):       0 =  0.0%       0 =  0.0%       1 =  0.0%       0 =  0.0%

==== Sats in use

Sat(GSA)  2:  5381 = 10.5%,  S/N( 1075), mit = 28.7, max = 44, min = 13, Ele = [10,48], Azi = [257,315]

Sat(GSA)  4:  5275 = 10.3%,  S/N( 1054), mit = 27.2, max = 46, min = 12, Ele = [40,63], Azi = [207,302]

Sat(GSA)  5:  2317 =  4.5%,  S/N(  459), mit = 25.6, max = 41, min = 12, Ele = [10,30], Azi = [298,307]

Sat(GSA)  7:  1429 =  2.8%,  S/N(  286), mit = 24.6, max = 37, min = 15, Ele = [63,70], Azi = [115,143]

Sat(GSA)  8:  1468 =  2.9%,  S/N(  294), mit = 22.2, max = 34, min = 13, Ele = [37,53], Azi = [180,181]

Sat(GSA) 10:  5291 = 10.4%,  S/N( 1059), mit = 28.7, max = 44, min = 12, Ele = [ 8,79], Azi = [277,332]

Sat(GSA) 11:  2927 =  5.7%,  S/N(  587), mit = 20.6, max = 37, min = 12, Ele = [11,81], Azi = [159,277]

Sat(GSA) 13:  6877 = 13.5%,  S/N( 1377), mit = 25.3, max = 42, min = 12, Ele = [16,85], Azi = [  1,359]

Sat(GSA) 14:   859 =  1.7%,  S/N(  174), mit = 20.3, max = 31, min = 12, Ele = [ 8,35], Azi = [ 38, 55]

Sat(GSA) 17:  3322 =  6.5%,  S/N(  664), mit = 23.6, max = 37, min = 12, Ele = [10,41], Azi = [219,289]

Sat(GSA) 19:  1115 =  2.2%,  S/N(  223), mit = 28.5, max = 40, min = 15, Ele = [26,35], Azi = [169,170]

Sat(GSA) 20:  3551 =  6.9%,  S/N(  709), mit = 21.5, max = 38, min = 12, Ele = [ 7,83], Azi = [ 70,327]

Sat(GSA) 23:  5327 = 10.4%,  S/N( 1065), mit = 23.2, max = 44, min = 12, Ele = [13,83], Azi = [ 48,189]

Sat(GSA) 24:  2886 =  5.6%,  S/N(  577), mit = 21.5, max = 36, min = 12, Ele = [21,85], Azi = [128,335]

Sat(GSA) 31:   745 =  1.5%,  S/N(  151), mit = 18.2, max = 33, min = 12, Ele = [14,24], Azi = [ 35, 50]

Sat(GSA) 32:  2342 =  4.6%,  S/N(  464), mit = 21.3, max = 39, min = 12, Ele = [26,80], Azi = [ 58,241]

==== Sats in view

Sat(GSV)  2:  1289 =  6.6%,  S/N( 1088), mit = 28.5, max = 44, min =  7, Ele = [ 1,48], Azi = [257,315]

Sat(GSV)  3:   174 =  0.9%,  S/N(   19), mit = 17.5, max = 22, min = 12, Ele = [ 1, 4], Azi = [163,163]

Sat(GSV)  4:  1503 =  7.6%,  S/N( 1270), mit = 25.9, max = 46, min =  8, Ele = [ 6,63], Azi = [207,307]

Sat(GSV)  5:   576 =  2.9%,  S/N(  467), mit = 25.3, max = 41, min =  7, Ele = [ 1,30], Azi = [290,307]

Sat(GSV)  7:  1109 =  5.6%,  S/N(  557), mit = 22.6, max = 37, min =  7, Ele = [ 2,71], Azi = [105,179]

Sat(GSV)  8:   853 =  4.3%,  S/N(  466), mit = 22.1, max = 34, min =  9, Ele = [ 1,53], Azi = [180,185]

Sat(GSV) 10:  1411 =  7.2%,  S/N( 1206), mit = 27.6, max = 44, min =  7, Ele = [ 1,79], Azi = [271,332]

Sat(GSV) 11:   766 =  3.9%,  S/N(  596), mit = 20.5, max = 37, min =  7, Ele = [ 1,81], Azi = [156,277]

Sat(GSV) 12:    49 =  0.2%,  S/N(   41), mit = 20.7, max = 27, min = 15, Ele = [ 1, 1], Azi = [350,352]

Sat(GSV) 13:  1536 =  7.8%,  S/N( 1475), mit = 25.1, max = 42, min =  7, Ele = [ 6,85], Azi = [  1,359]

Sat(GSV) 14:   307 =  1.6%,  S/N(  267), mit = 20.8, max = 37, min =  7, Ele = [ 1,37], Azi = [ 38, 58]

Sat(GSV) 16:   949 =  4.8%,  S/N(  200), mit = 21.1, max = 37, min =  7, Ele = [ 1, 5], Azi = [ 27, 74]

Sat(GSV) 17:  1227 =  6.2%,  S/N(  869), mit = 22.7, max = 39, min = 10, Ele = [ 3,41], Azi = [211,317]

Sat(GSV) 19:   225 =  1.1%,  S/N(  225), mit = 28.4, max = 40, min =  9, Ele = [26,35], Azi = [169,170]

Sat(GSV) 20:  1629 =  8.3%,  S/N(  807), mit = 21.5, max = 38, min =  7, Ele = [ 1,83], Azi = [ 70,327]

Sat(GSV) 22:   225 =  1.1%,  S/N(   34), mit = 16.5, max = 25, min =  7, Ele = [ 1, 8], Azi = [ 61, 64]

Sat(GSV) 23:  1727 =  8.8%,  S/N( 1323), mit = 22.8, max = 44, min =  7, Ele = [ 1,83], Azi = [ 48,193]

Sat(GSV) 24:   908 =  4.6%,  S/N(  586), mit = 21.4, max = 36, min =  7, Ele = [ 1,85], Azi = [128,335]

Sat(GSV) 25:   294 =  1.5%,  S/N(   28), mit = 17.1, max = 27, min =  8, Ele = [--,--], Azi = [  2, 11]

Sat(GSV) 26:   243 =  1.2%,  S/N(   31), mit = 16.8, max = 23, min = 13, Ele = [ 1, 9], Azi = [249,257]

Sat(GSV) 28:   225 =  1.1%,  S/N(  140), mit = 19.8, max = 34, min =  9, Ele = [14,19], Azi = [274,282]

Sat(GSV) 30:   511 =  2.6%,  S/N(    3), mit = 16.3, max = 17, min = 16, Ele = [ 1, 2], Azi = [ 33, 52]

Sat(GSV) 31:   716 =  3.6%,  S/N(  357), mit = 19.4, max = 38, min =  7, Ele = [ 1,26], Azi = [ 27,113]

Sat(GSV) 32:  1185 =  6.0%,  S/N(  489), mit = 21.0, max = 39, min = 10, Ele = [ 1,80], Azi = [ 58,241]

Sat(GSV) 33:    17 =  0.1%,  S/N(   17), mit = 27.1, max = 33, min = 22, Ele = [29,39], Azi = [205,211]

Sat(GSV) 34:     1 =  0.0%,  S/N(    1), mit = 28.0, max = 28, min = 28, Ele = [--,--], Azi = [---,---]

Sat(GSV) 37:    21 =  0.1%,  S/N(   21), mit = 27.2, max = 33, min = 23, Ele = [32,38], Azi = [151,164]

Sat(GSV) 39:     1 =  0.0%,  S/N(    1), mit = 31.0, max = 31, min = 31, Ele = [31,31], Azi = [159,159]

==== GPS Fix Infos

GSA-Fix 1:    33

GSA-Fix 2:   203

GSA-Fix 3:  8574

RMC-FAA A:  8810 = 100.0%

GGA-FixQual 0:    33 =  0.4%

GGA-FixQual 1:  8777 = 99.6%

References