Difference between revisions of "ASTER topography"

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<p style="font-size: 150%; text-align: left;">'''Attention'''&nbsp;</p>'''The following instructions concern the first release of the ASTER GDEM data base. The public distribution of a second, much improved version, started in October 2011 (refer to [http://www.jspacesystems.or.jp/e/ Japan Space Systems'] [http://www.jspacesystems.or.jp/ersdac/GDEM/E/ ASTER GDEM dedicated website] for [http://www.jspacesystems.or.jp/ersdac/GDEM/E/4.html details] and [http://www.jspacesystems.or.jp/ersdac/GDEM/ver2Validation/Summary_GDEM2_validation_report_final.pdf a high-level validation study]).'''
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<p style="font-size: 150%; text-align: left;"><span style="color:#35824B">'''Attention'''</span>&nbsp;</p><span style="color:#303030">'''The following instructions concern the first release of the ASTER GDEM data base. The public distribution of a second, much improved version, started in October 2011 (refer to [http://www.jspacesystems.or.jp/e/ Japan Space Systems'] [http://www.jspacesystems.or.jp/ersdac/GDEM/E/ ASTER GDEM dedicated website] for [http://www.jspacesystems.or.jp/ersdac/GDEM/E/4.html details] and [http://www.jspacesystems.or.jp/ersdac/GDEM/ver2Validation/Summary_GDEM2_validation_report_final.pdf a high-level validation study]).'''</span>
  
 
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Revision as of 16:59, 31 December 2012

Download

The one-by-one-degree tiles can be downloaded

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

See also