[GRASSLIST:6302] Re: GPS points off by about 120m to the west

[Hamish]

> thanks for the information on this -- i was using v.in.ascii to import
> these points ... thinking that the GPS would be exporting my points in
> 
> NAD83/UTM as the GPS unit was configured to use. i will give it a try 
> with the CVS copy of v.in.garmin a little later this week.
> 
> on a related note, if i am sending points to the GPS- they would need 
> to be transformed to WGS84 as well?


I think so, but I'm not 100% sure. I usually just try to keep the GPS in
lat/lon WGS84 to keep things sane. I see that 'gpstrans -s' lets you
pick a datum and UTM format. The top of the gpstrans output, it lists
what you are using I think. Also note Garmin protocol outputs GMT, not
local time as displayed on GPS display.

gpsbabel?


> maybe cs2cs can do this for me?

well sure. v.in.garmin uses cs2cs to do just this.

I've been meaning to port the m.proj2 module from GRASS 5.4 to GRASS 6
(well a functional replacement anyway) which will do WGS84 import/export
from a list of coordinates. Still haven't got to it, partly because I
haven't figured out a good name for it (g.reproj, g.pointproj ??),
partly because I haven't figured out how to get a shell script to accept
input piped from stdin (as well as a file). The main part of the script
is actually very simple so the only reason to do it in C is if I can't
figure out how to support the dual input methods.


Hamish