Importing and Exporting from/to a Garmin GPS

Importing and exporting GRASS vector data from/to GPS unit can be done in many ways. The commands v.in.garmin and v.in.gpsbabel work well for importing track and waypoint data from a GPS. Note however that v.in.garmin requires points and track data to be stored in decimal degree format. A simpler approach for dealing with both import and export of vector data from GRASS cab be done with a little bit of awk and the program gpstrans. A few common examples are listed below. Command names are in boldface type, input files are red, and the resulting GRASS data are in green.

Gpsbabel

From GRASS

# garmin-specific notes here
http://www.gpsbabel.org/htmldoc-1.3.2/fmt_garmin.html

1. dowload data vis gpsbabel to GPX:
 - import with v.in.gpsbabel
 - convert directly to shp with gps2shp:
   http://gpx2shp.sourceforge.jp/  (source)

Samples from the command line.

# download waypoints from garmin to GPX file
gpsbabel -i garmin -f /dev/ttyS0 -o gpx -F garmin_points.gpx

# download track from garmin to GPX file
gpsbabel -t -i garmin -f /dev/ttyS0 -o gpx -F garmin_track.gpx

# upload to garmin GPS
gpsbabel -i gpx -f garmin_points.gpx -o garmin -F /dev/ttyUSB0

Gpstrans

Import all way points with labels starting with "0":

#download all waypoints from gps
gpstrans -dw > all_wpts_5-3.ascii
#output from gpstrans looks like:

Format: UTM  UTC Offset:  -7.00 hrs  Datum[066]: NAD83
W       001     01-MAY-06 22:58                                 12/31/1989 -7:00:00     10      S       0662251 4039089
W       002     01-MAY-06 23:20                                 12/31/1989 -7:00:00     10      S       0661915 4039282
W       003     01-MAY-06 23:36                                 12/31/1989 -7:00:00     10      S       0662224 4039287
W       004     02-MAY-06 00:06                                 12/31/1989 -7:00:00     10      S       0662002 4039768

#import only those which start with "0" into GRASS
awk '{OFS="|"} $2 ~ /^0.?/{print $9,$10,$2}' all_wpts_5-3.ascii | v.in.ascii out=new_vector columns="x int, y int, id varchar(3)"

Export from points to Garmin GPS:

v.out.ascii spring3 dp=0 | \
awk -F"|" '
BEGIN{
OFS="\t"; print "Format: UTM  UTC Offset:  -7.00 hrs  Datum[066]: NAD83"
}
{
print "W\tP"$3"     \t28-MAR-07 20:35                         \t12/31/1989 -7:00:00\t10\tS\t0"$1"\t"$2
}
' > garmin_points.waypts

Export new route to Garmin GPS: