Is there a way in GRASS, 6.3 to take a raster map of say the SW United States and use a vector cutter to cut out a smaller portion of the map in order to run certain statistics on it. For example, if I have a temperature raster for the SW United States and I wanted to cut an area which I have coordinates for like Los Alamos, is there a way to cut out this area of the map and reproject in order to run mean, st.dev, etc.
Thanks,
Aaron
goldneaa@onid.orst.edu wrote on 07/17/2007 05:21 PM:
Is there a way in GRASS, 6.3 to take a raster map of say the SW United
States and use a vector cutter to cut out a smaller portion of the map
in order to run certain statistics on it. For example, if I have a
temperature raster for the SW United States and I wanted to cut an
area which I have coordinates for like Los Alamos, is there a way to
cut out this area of the map and reproject in order to run mean,
st.dev, etc.
Yes: v.select and v.overlay.
See the (maybe little outdated) tutorial
http://grass.itc.it/grass51/tutorial/vectoroverlay.html
and the module descriptions (g.manual v.select | g.manual v.overlay
Also v.extract can be useful to extract via attribute.
Then run v.rast.stats to calculate the statistics:
g.manual v.rast.stats
Markus
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ITC -> dall'1 marzo 2007 Fondazione Bruno Kessler
ITC -> since 1 March 2007 Fondazione Bruno Kessler
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On Tue, 2007-07-17 at 08:21 -0700, goldneaa@onid.orst.edu wrote:
Is there a way in GRASS, 6.3 to take a raster map of say the SW United
States and use a vector cutter to cut out a smaller portion of the map
in order to run certain statistics on it. For example, if I have a
temperature raster for the SW United States and I wanted to cut an
area which I have coordinates for like Los Alamos, is there a way to
cut out this area of the map and reproject in order to run mean,
st.dev, etc.
I tend to use `v.extract` to "cut out" the vector polygon I want to use
as a region, convert it to a raster with `v.to.rast use=val val=1 ...`,
and do my final raster operation with the new raster as a mask
(`r.mask`).
I'm sure there are several other ways.
--
Brad Douglas <rez touchofmadness com> KB8UYR/6
Address: 37.493,-121.924 / WGS84 National Map Corps #TNMC-3785