[GRASS-user] How to Import and Export Maps Using Grass

[Markus Neteler]

On Sat, Jan 16, 2010 at 3:46 PM, David Benman <dave at dbenman.com> wrote:
>
> I am programming a flight simulator and need to create landscape imagery. I
> have downloaded the New York State orthoimagery available at
> http://www.nysgis.state.ny.us/gateway/mg/2006/onondaga/
>
> I now need to combine several image tiles into one,

This would be the r.patch command:
http://grass.osgeo.org/grass64/manuals/html64_user/r.patch.html

Procedure:
g.region rast=map1,map2,map3[,map4...] -p
r.patch input=map1,map2,map3[,map4...] output=hugemap

> reduce their resulting size

That's r.resamp.stats - Resamples raster map layers to a coarser grid
using aggregation.
http://grass.osgeo.org/grass64/manuals/html64_user/r.resamp.stats.html

g.region res=xx
# with xx a number which is the destination pixel resolution
r.resamp.stats input=hugemap output=hugemap_lowres

Then export (e.g. GeoTIFF):
r.out.gdal input=hugemap_lowres output=hugemap_lowres.tif

>, etc. How can I do this with Grass? I have never used Grass, but hope
> somebody could point me to some applicable tutorials or outline the major
> steps.

Hope above gives an indication. Otherwise there is material here to read:
http://grass.osgeo.org/gdp/

Markus