I have some topo maps (in GeoTIFF format from Teale Data
Center). I want to crop the 'collars' (the white space around the map
itself) then join adjacent maps at their boundaries to create one new
map. I have looked at GRASS, read docs, and followed tutorials for
hours and not figured out how to do this. I hope this indicates great
obtuseness on my part. Would some kind soul point me in the right
direction?
Thanks.
russell bell
On Sat, Apr 14, 2001 at 04:47:40PM -0700, Russell A. Bell wrote:
I have some topo maps (in GeoTIFF format from Teale Data
Center). I want to crop the 'collars' (the white space around the map
itself) then join adjacent maps at their boundaries to create one new
map. I have looked at GRASS, read docs, and followed tutorials for
hours and not figured out how to do this. I hope this indicates great
obtuseness on my part. Would some kind soul point me in the right
direction?
Thanks.russell bell
You, of course, know Teale already has such things.
One way, might involve a combination of v.mkgrid, v.proj, g.region, and
r.mapcalc.
In lat/lon nad27/clark66 location, make a vector box corresponding to
the quad edges for each quad. Then project each vector box to your
Teale Albers coordinate system. Then use g.region twice, first on the
DRG of interest, then on it's corresponding vector extents (sans edge
markings). The first g.region will help to match the cell size for that
quad correctly, while the second will limit the area of interest. Then
GRASS ~> echo 'trimquad = oldquad' | r.mapcalc
The r.mapcalc trick should work, since only the cell values in the
region you've defined will be copied into the new quad. The color map
may need to be reassigned, but that's trivial with r.colors.
Most of this could probably be scripted with a shell script provided you
use a consistent naming nomenclature (similar to the O34119A6.tif or
whatever, hint Teale's trimmed quads are like T34119A6.tif).
--
Eric G. Miller <egm2@jps.net>
Howdy folks,
Could someone tell me if there is a way to create a new location and
mapset from the command line.
I am writing a batch job to process a ton of imagery and the most
cost(time/cpu) effective way I have found to do this requires creating a
new location for every image and then importing the result into the final
map.
Thanks ahead,
Matt
On Mon, Apr 16, 2001 at 10:39:22AM -0400, mberglund wrote:
Howdy folks,
Could someone tell me if there is a way to create a new location and
mapset from the command line.I am writing a batch job to process a ton of imagery and the most
cost(time/cpu) effective way I have found to do this requires creating a
new location for every image and then importing the result into the final
map.Thanks ahead,
Matt
Hi Matt,
you can use (GRASS 5): r.in.gdal
The "-e" flag and "location=" parameter allow to generate a
new location through another, different location.
But: if your input data do not provide projection data, you have
to set this with g.setproj later within the new location.
See here as well:
http://www.geog.uni-hannover.de/grass/gdp/html_grass5/html/r.in.gdal.html
Cheers
Markus Neteler