This is the GpsDrive FAQ.
This file is maintained by Fritz Ganter.

Q: Why is this file so short?
A: I'm still working on it.

Q: GpsDrive 2.x: After compiling Gpsdrive from source, I have the
   problem that GpsDrive will not display the map when it's running.
   All of the graphics in the map area are blank. 
A: Compile with gcc 3.x, this bug is know at least with debian and
   slackware.

Q: GpsDrive shows "Not enough satellites in view" in the statusbar and don't
   display my position.
A: You need at least 3 satellites in view to get a valid position. It may also
   take some minutes to get a valid position. You have to be outside under
   clear sky; GPS mostly doesn't work inside the house. Trees, houses or other 
   barriers can prevent your GPS receiver getting a valid position.
   Some GPS receivers have a "Simulation mode" which sends position 
   signals, but with a "invalid position" flag. GpsDrive won't display
   a position if this "invalid position" flag is set. To override this
   (do it only for testing!!!) you can call GpsDrive with the 
   "-F" command line parameter.
   
Q: I have a USB GPS receiver, it works fine with GpsDrive but if I
   leave the program, Linux crashes.
A: This is a bug of the "Prolific PL2303 USB to serial adaptor driver"
   which is used. The crash happens if the serial device is
   closed. This bug is kernel >=2.4.19
   One solution is to use a kernel 2.6.x where this
   bug is fixed, or 2.4.18 where it doesn't appear.

Q: Why is there no street navigation which gives turn by turn
   directions?
A: Turn by turn directions are not possible with GpsDrive at the present
   because no opensource data is available which represents the street
   coordinates in a form usable for that purpose.  GpsDrive currently
   works with bitmap images rather than vector data.
   We are working together with the OpenStreetMap Project to get there.
   As you can see the first attemts to use OpenStreetMap.org Data to 
   do route finding (outside of GpsDrive) where already successfull.
   So we can hope for this feature in the future.

Q: What is GpsDrive?
A: GpsDrive is an open source navigation system. It displays your current
   position provided by an NMEA capable GPS receiver(connected to gpsd)
   on a zoomable map.

Q: How do I install GpsDrive on a Linux box?
A: This depends on the Distribution you're using.
   On Debian Systems you can use the debian repository at http://www.gpsdrive.de/debian/
   On other Systems I recommend to use the source tarball. Download it from 
   http://www.gpsdrive.de/.
   Unpack the tarball with `tar xvzf gpsdrive-X.XX.tar.gz` where X.XX is the version
   number. Now change into the directory gpsdrive-X.XX and run `./configure`.
   Some people (including me, Sven) don't like the Garmin protocol. It can
   be easily disabled with the option `--disable-garmin`. Now run `make`.
   Depending on your CPU power this will take something between 4 seconds and
   3 minutes. An Intel Celeron 1000 takes approximately 50 seconds to have
   the version 1.28pre1 compiled. Now do a `su`, enter your root password and
   continue with a final `make install`.

Q: I am running FreeBSD. Can I use GpsDrive too?
A: Yes. See the file README.FreeBSD for further information.

Q: I'm trying to run GpsDrive on iPAQ, but I don't have /dev/ttyS0.
A: You may want to use /dev/tts/0. When using gpsd, you will have to change
   some parameters in /etc/gpsd.conf. Use -p /dev/tts/0 and -s4800.

Q: I'm too lazy to get out of my bed, how can I test with my GARMIN GPS III?
A: Your GARMIN has a built in simulator. Start it on the "satellite screen",
   then go to setup and enter a speed in the simulator menu. Then
   "goto" a stored waypoint and look how fine GpsDrive works. Don't forget 
   to download your maps first.

Q: How can I get detaled maps to be displayed?
A: Either you use Openstreetmap Data with Mapnik in Combination.
   or 
   You Download PixelMaps with the "Download map" button located under
       Options - Maps - Download.
   After pressing it, a new window will appear. 


Q: Can I download multiple maps covering a larger area?
A: There is a script called "gpsfetchmap.pl" provided. Use the "-h" option
   to get a help screen.

Q: Can I use own maps?
A: Yes. Of course you can use your own (self drawn, scanned...) maps. The
   maps must be gif, jpeg, png or other common file formats (the format
   must be recognized by the gdk-pixbuf library).  The lat/long coordinates
   you write into the "map_koord.txt" file must be the center of the map.
   The map must have a size of 1280x1024 pixels! Important! The maps must be
   named map_* for streetmaps and top_* for topographical maps. If not,
   GpsDrive won't display the maps. GpsDrive comes with an import assistant.
   Simply use the Menu item Options->Maps->import and follow the instructions.

Q: What is the mapnik?
A: Manik is a renderer for Openstreetmap data. You can active the mapnik mode
   by checking the mapnik option (map controls).

Q: There is no mapnik option?
A: It is only available if you have installed the mapnik packages. Have a look
   at install-mapnik-osm.txt.

Q: Which GPS receivers work with GpsDrive?
A: Any receiver that is recognized by gpsd should work. 

Q: Which receiver is the best one?
A: This is a religious question, just like the one for the best editor or mail
   client (which is vi and mutt).
   Fritz: No, off course its emacs and evolution.
   Joerg: Alsmost; is's emacs and kmail ;-)
   
Q: How can I use the Holux GM-200 USB with GpsDrive?
A: This device has the Prolific PL-2303 chip in it for the USB => Serial
   conversion.  The USB => Serial "pl2303.c" driver seems to work pretty
   well!
   
   Quick Start:

   Build GPSDrive (Requires GTK 2)
   Build new kernel (or module) using "USB Prolific 2303 Single Port Serial
   Driver (EXPERIMENTAL)" Load the new kernel || module
   Do: `mknod /dev/ttyUSB0 c 180 0` (If it doesn't already exist)
   Do: `chmod 666 /dev/ttyUSB0`
   Do: `gpsd -p /dev/ttyUSB0`
   Do: `gpsdrive`
   (provided by Todd E. Johnson)
   Hint: You want to use a kernel >= 2.4.18. ;)


Q: Why is such funny english used in gpsdrive?
A: Fritz is from Austria and speaks the same kind of "english" as Arnold
   Schwarzenegger.

Q: Can I use GpsDrive without a GPS receiver?
A: Yes.  You might want to do this when you have a fast internet connection
   for downloading maps etc.  Also, you can use it to review stored journey
   tracks (see below).

Q: Does GpsDrive handle 'tracks' saved in my GPS receiver?
A: Yes. Use a tool like 'gpsbabel' to convert them into GPX format.
   [Please expand this answer.]

Q: I know that we aren't supposed to use GpsDrive 'for navigaton purposes' -
   but is it any use to (student) aviators?
A: Certainly - pack your GPS unit in your flight bag (turned on of course!),
   then download the tracks into GpsDrive when you get home.  It's a great way
   to see exactly how good your navigational skills are - or maybe where you
   busted airspace!  Flying schools could use this to analyse students' solo
   navigational trips.
   
Q: I have also noticed that the unique ID sent to my Friendsd2 server from
   my gpsdrive is not unique
   Is there a way to manually set the unique ID to correct this problem?
A: Have a look at ~/.gpsdrive/gpsdriverc:
      friendsidstring = XXX
   If you delete the key in the file or set it to XXX you should get a new 
   FriendsID.

Q: My gps seems like being always behind the actual position. It seems like 
   I'm 13seconds behind.
A: The problem isn't gpsd or gpsdrive, the problem is the SiRF firmware. Check
   the gpsd mailinglist.
   If the GPS device is in SiRF mode, gpsd translates SiRF binary mode to NMEA
   mode and you'll get a lag of about 13 sec. But if you set the device to
   NMEA mode, it will work just fine.
   The question is if gpsd should provide the possibilty to start the GPS
   device with NMEA mode or if there should be an option in gpsdrive. The
   default is always the binary mode because it will provide more
   informations.
   Solution for gpsdrive users: 
	gpsd_nmea.sh        

Q: if i download 5m, 500k, 50k and 5k and open gpsdrive, i get
   the smallest map that i can not zoom out at all.
A: If you're using automap gpsdrive alway displays the map with 
   the smallest resolution it can find. Changing the scale 
   has no effect while autobestmap is on.

Q: if 'auto best map' is disabled, i sort of can choose scale at the lower
   right corner, but i can not zoom in from the biggest view and get small
   scale maps automatically...
A: If autobestmap is disabled gpsdrive should select the smallest-scale map
   greater then your suggested scale.
   With "Pref. scale" you tell gpsdrive which scale you'd prefer to have. 
   Then gpsdrive has a look at every map in map_koord.txt to see which map 
   is in sight with a map-scale >= pref-scale.

Q: I also can not find a way to move the map (as i can see larger area in
   lower left hand corner...)
A: If you click on pos-mode. You can set your Car-Position in Gpsdrive to
   any location on the map. If your car-position is in the outer ~10% of 
   the map gpsdrive tries to see if there is a map available which 
   would fit better for your Position.

Q: What is the map projection GPSDrive uses?
A: To be picky, as it is critical to be picky in order to get this stuff
   working correctly:  (especially with gdalwarp & PROJ4 parameters)
   WGS84 defines both a datum & an ellipsoid, but not a projection. The
   projection is lat/lon (well, it's unprojected I guess).

   Here are some links to primers on Geodesy (Projections and Datums):
   http://grass.gdf-hannover.de/twiki/bin/view/GRASS/GisConcepts

   To answer your question though,

   If you title the image "map_*" the projection is assumed to be UTM-like
   (preserves equal area); if the map is named "top_*" it is assumed to be
   "Plate Carrée"*, ie equi-rectangular 1:1 lat to lon.

   UTM-like will be scaled 1:cos(lat) in the x and y dir. If you can draw
   grid or add test points to the image, you can check against grid lines
   or self-entered waypoints in gpsdrive to make sure everything is
   matching.

   [*]  http://en.wikipedia.org/wiki/Plate_carr%C3%A9e_projection

Q: Converting Old Maps
A: If you have old expedia maps on your system and want 
   to reuse them you should move them to a 
   subdirectory ~/.gpsdrive/maps/expedia/ 
   and add expedia/ before every map entry in map_koords.txt
   then you can take map_koord.txt and move it one directory
   down to  ~/.gpsdrive/maps/map_koord.txt

   Any other map should be moved in a similar way.

Q: What's this "no dir" checkbox in the maps Section 
A: This is because of the change in the map directory structure. See below

Q: I'm missing the "download map" button
A: It was moved into the menu, since normally you don't need it while driving.

Q: After Upgrading I don't see any maps. But the old .gpsdrive dir 
   is still there with the maps.
A: We have a new map directory structure.
   You'll have to create a directory .gpsdrive/maps/... .
   The tree then will look like:
   ~/.gpsdrive/maps/mapservice-xy/...
   And your map_koord.txt is now located in the 
	~/.gpsdrive/maps/
  Directory and look like this:
 top_Africa.jpg         0.0     25.0     30000000
 top_America.jpg       10.0    -90.0     40000000
 top_Australia.jpg    -24.700  132.3     11651916
 top_Europe.jpg        52.5     12.0     11000000
 top_Germany.jpg       51.0     11.9      3500000
 top_GPSWORLD.jpg       0.0      0.0     88067900
 top_NorthAmerica.jpg  37.8167 144.9667  20000000
 top_SouthAmerica.jpg -20.0    -80.0     20000000
 top_WorldEast.jpg     30.0   -100.0     40000000
 eniro/1000000/57/57.4/11/map_1000000-57.4-11.6666666666667.gif 57.4000000000000, 11.6666666666667, 592500
 ...
 landsat/500000/49/12/map_500000-49-12.8333333333333.gif  49.0000000000000  12.8333333333333    500000
 ...

  where the top_Africa.jpg maps come from the system directory.
