[GRASSLIST:964] Re: Newbie Problem with Raster File Import GRASS 5

[Johannes Bühler]

Hi
> 
> g.region gives me this:
> 
> CURRENT REGION: N=41:37:48.36N  S=41:32:48.48N  RES=0:00:00.36 
> ROWS=833
>                 E=74:53:43.44W  W=75:02:35.52W  RES=0:00:00.36 
>                 COLS=1478
> PROJECTION: 3 (Latitude-Longitude)
> ZONE:       0
> DATUM:      ** unknown (default WGS84) **
> ELLIPSOID:  wgs84

> I have a tiff image from topozone with an associated tfw file that
> shows this:
> 
> 5.0800000000
> 0.0000000000
> 0.0000000000
> -5.0800000000
> 495812.6492529264
> 4609362.2176114470
Do you know the projection of this tfw file? You will need it if you
want to transfor it into your lat/lon location. 

you find some general information on
http://grass.itc.it/gdp/grass5tutor/HTML_en/c1418.html

see the man page (man r.proj) for detailed information, how to
convert a raster file into another projection.

 
> I suspect that the region's latitude doesn't accommodate the tfw
> file's parameters but I'll be darned (or worse) if I can figure
> how the region needs to be changed.

If you dont have any projection information for the raster file.
just set up an x,y location in grass an import the raster file
unprojected. set the region extend to the raster file's boundaries,
you have mentioned above.

> 
> The raster file is really the set of boundries that I wanted, how
> do I convert the tfw file's easting/northing information to
> lat/lon (if that is the appropriate way to fix the issue?

see man r.proj (This assumes that you have compiled with proj4
support.

> 
> Any help would be appreciated.

Hoped that helped

Johannes


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