[GRASS-dev] Re: [GRASS GIS] #789: g.region option to expand the
computational region of about "some" pixels?
GRASS GIS
trac at osgeo.org
Thu Oct 15 08:07:48 EDT 2009
#789: g.region option to expand the computational region of about "some" pixels?
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Reporter: nikos | Owner: grass-dev at lists.osgeo.org
Type: enhancement | Status: new
Priority: normal | Milestone: 7.0.0
Component: default | Version: unspecified
Resolution: | Keywords: g.region, expand computational region
Platform: Unspecified | Cpu: Unspecified
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Comment (by nikos):
Replying to [comment:5 hamish]:
> Replying to [comment:1 hamish]:
> > did you try the g.region align=rastermap option?
This works fine. Nevertheless, what I want to do is a bit more
complicated:
* I have X raster and Y point vector maps.[[BR]]
* Each point vector map has one column for each raster, that is at least
X columns (+cat +the typical rows, cols columns).[[BR]]
* I want to update the X columns in each point map with the values from
the (X) raster maps (one column per raster map of course).[[BR]]
So what I do in my script is (in pseudocode):
{{{
for point_map in group_of_point_maps:
g.region vect=point_map
for Raster in group_of_rasters:
v.what.rast vect=point_map rast=Raster column=Raster
}}}
This is where the problem arises since I can't use the align=ToRasterMap
option. To make the long story short it is required:[[BR]]
a. to loop over a series of point vector maps whose columns are to be
updated[[BR]]
b. to (sub-) loop over a series of raster maps from which the vector
columns will be updated (for each point vector map).
How to solve this? Maybe it's a common problem but I don't know how to
deal with it than just use a basic naming convention for all maps and play
later with string manipulation utilities (such as cut, tr, sed, etc in
bash or the likes in python). So, I was thinking that a "better" g.region
option would make things easier when "align=ToRasterMap" is not an
option.[[BR]]
Currently I don't have a problem because, as I described in the very
beginning, I have the original vector grids from which the point maps
derived and it's easy to use them (almost same name) in the "g.region"
command in order to get a larger region.
Hope this is now clear. Thanks, Nikos
--
Ticket URL: <http://trac.osgeo.org/grass/ticket/789#comment:7>
GRASS GIS <http://grass.osgeo.org>
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