It's been a while since I imported some DRG's, but I think the procedure
was fairly easy. A word of caution, I obtained my DRG's from the Nevada
Bureau of Mines so I'm not sure if the file structure is the same as those
DRG's obtained directly from USGS. At NBM the DRG's came as three files: a
.tif image file, a .tfw world file, and an .fgd metadata file.
I used r.in.tiff to bring the DRG into GRASS, then I used r.support to
change the header using data supplied in the .tfw and .fgd files to
georeference the DRG. The .tfw or World file supplies the n-s and e-w
resolution (typically 10.16 m) and the utm coordinates for the northwest
corner of the image. The .fgd or Metadata file supplies the number of
rows and columns and utm zone for the image. You multiply the rows and
columns by the resolution to obtain the east and south boundaries. Hope
this helps.
Don Ebert
Research Associate
National Biological Service
Cooperative Research Unit
University of Nevada - Las Vegas
On Tue, 27 Aug 1996, Malcolm Williamson wrote:
(Note: this is a re-send, as I don't think my first version made it out -
new list address?? Anyway, my humble apologies if it did!)Hello, all
Has anyone developed, or heard of, a GRASS module for importing the
USGS's Digital Raster Graphics (DRG) product? We don't want to re-invent
the wheel...Many thanks (and apologies to folks that subscribe to
both lists!),
-Malcolm
--
Malcolm D. Williamson - GIS Specialist E-mail: malcolm@cast.uark.ed
u
Center for Advanced Spatial Technologies Telephone: (501) 575-6159
Ozark Rm. 12 Fax: (501) 575-5218
University of Arkansas
Fayetteville, AR 72701