[GRASSLIST:3315] Re: GPS - Raster overlay

[Paul Wefel]

That is a good idea.  Thanks for the suggestion.
Looks like m.ll2u will do the conversions for me.
I'll give it a try today.

On Fri, Mar 08, 2002 at 10:31:13AM -0600, Keene Haywood wrote:
> >Hi, 
> >
> >I am relatively new to the world of GIS and escpecially GRASS.  What I am
> >trying to do is to plot a track from my Garmin GPS and then plot specific
> >points on top of that track.  Then I would like to overlay that data ontop of
> >a digital orthophoto quarter quad.
> >
> >I have written the necessary Perl glue to convert the GPS data so that
> >s.in.ascii will import it.  I created a location in grass5 using lat-long and
> >set the boundaries to be equal to the lat-long boundaries of my DOQ.  I then
> >used d.sites to display my track data and point data.  This worked well.
> >
> >Next I opened the MrSid formatted DOQ in a MrSid viewer and saved it as a
> >GeoTiff file.  I then tried to import the geotiff into my lat-long region
> >using both r.in.tiff and r.in.gdal but kept getting errors about north lat
> >out of range.
> >
> >I did some searching on the lists and found a suggestion to import the
> >geotiff into a new location defined as x-y and set to equal the resolution
> >of the geotiff,  I did this and was able to import the file and display it
> >with d.rast.  Now I am trying to move either the lat-long sites data into
> >the x-y location or move the x-y raster into the lat-long location. 
> >
> >Any suggestions on how I can get the lat-long data to overlay the DOQ?
> >
> >Thanks, 
> >
> >-paul
> >
> >-- 
> >/- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -\
> >|Paul Wefel            NCSA                 Network Engineer    |
> >|phone: 217-244-2193   cell: 217-840-9929   pwefel at ncsa.uiuc.edu|
> >|CAB 269, 605 E Springfield, Champaign IL 61820                 |
> >\- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -/
> >
> Hi Paul
> 
> You might try switching your GPS data to UTM coordinates before
> downloading them and then try overlaying them.  The DOQ file is probably
> in UTM coordinates.  This might be a solution if you are willing to use
> UTM instead of Lat/Long.
> 
> Keene