[GRASSLIST:6284] GPS points off by about 120m to the west

[Dylan Beaudette]

Greetings!

after retrieving some waypoints from my Garmin 12 GPS, i noticed that when 
imported into GRASS, they were offset by about 120 meters to the west....!

here is a picture of the bad (red) points, and corrected (blue) points:
http://basho/~dylan/temp/bad_gps.png


i am nearly positive that the data in GRASS is good: in NAD83/WGS80 UTM zone 
10N projection.

the GPS was set for the same projection parameters...

any ideas on what could have caused this 120meter shift to the west? 

could my GPS really be in a NAD27 datum, and still be reporting NAD83 ? 

any ideas? .

thanks in advance!


-- 
Dylan Beaudette
Soil Science Graduate Group
University of California at Davis