[GRASSLIST:2032] Re: GRASS and USGS images on terraserver.microsoft.com

[Frank Warmerdam]

Nathaniel Pendleton wrote:
> 
> Can these image and the "world file" work easily with GRASS?
> 
> USGS black and white images in
> 1, 2, 4, 8, 16, 32, 64, and 128 meter resolution JPGs
> AND
> "world file" for GIS are available for FREE at
> http://terraserver.microsoft.com
> 
> find the image desired, and click on USGS logo (top right)
> then down load the image and the save the worldfile as a ".jpgw"
> 
> data could would be something like this.
> [start snip]
> 16.000000
> 0.000000
> 0.000000
> -16.000000
> 313600.000000
> 4307200.000000
> [close snip]
> 
> Can these image and the "world file" work easily with GRASS?

Nathaniel,

In GRASS 5 you can use r.in.gdal to import JPEG files if you have GDAL support
with your GRASS.  However, changes to GDAL to support world files was only 
added in May, so you would need a GDAL built from CVS, since that feature was
not in GDAL 1.1.4. 

You could also use older GDAL builds and fix the georeferencing yourself after
import, or use some external utility (such as gdal_translate) to convert the
JPEG to TIFF format, and then r.in.gdal will honour the world file.  

Note that the world file should have the extension .jgw to use with r.in.gdal
for JPEG files.  It should have the extension .tfw to use with TIFF files.

Best regards,

---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent