ASTER topography
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Download
The one-by-one-degree tiles can be downloaded
- from NASA's EOS data archive and/or
- from Japan's Ground Data System
Importing ASTER GDEM tiles in GRASS' data base
Mosaicking ASTER GDEM tiles
Mosaicking all tiles can be done with gdalwarp and wildcards:
gdalwarp AST*.tif aster_mosaic.tif
The big aster_mosaic.tif can be imported in GRASS' data base as usual by using the r.in.gdal module.
Importing individual ASTER GDEM tiles in GRASS
# save downloaded zip files in one directory
# enter in directory and unzip files at once
unzip "*.zip"
# create WGS84 location, import elevation (=dem) and quality (=num) tiles in PERMANENT mapset
for GDEM in *.tif ; do
r.in.gdal in=$GDEM out=`basename ${GDEM} .tif`
done
# match region to extent of imported gdem tiles
g.region rast=`g.mlist pat=AST*dem sep=,` -p
# patch tiles in one map
r.patch in=`g.mlist pat=AST*dem sep=,` out=aster_gdem
# assign colors
r.colors aster_gdem color=terrain
Special color rules
Below are some starter color rules attempting to replicate NASA's "GDEM press colorized topo" published at "Mission News".
# create a file (named for example '''aster_gdem''')
# under the directory '''/etc/colors'''
# within the local grass installation (e.g. '''/usr/local/grass-6.4.0svn/etc/colors/aster_gdem''')
# copy-paste the following rules
-11000 black
-500 0 0 10
-300 0 0 20
-200 0 0 70
-100 0 0 130
-50 0 0 205
0 black
0.1 123 123 164
50 123 123 255
100 41 156 41
160 164 180 41
350 230 230 41
610 164 205 41
1100 164 213 41
1200 213 255 148
1500 205 255 139
2000 215 255 155
2300 238 238 24
3000 255 255 0
3800 255 213 41
4000 255 150 0
5500 255 255 255
nv white
# apply colors
r.colors aster_gdem color=aster_gdem