Difference between revisions of "Global datasets"

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=== Global Multi-Resolution Topography (GMRT) ===
* Global ~1 arc-second (~90 m) topography using multi-beam and satellite data in the oceans combined with SRTM on land.
* Full information at: http://www.marine-geo.org/portals/gmrt/
* Accessible via [http://www.geomapapp.org/ GeoMapApp] or [http://www.virtualocean.org/ Virtual Ocean] software.
* Very convenient to download into GRASS via wget:
  export `g.region -g`
  wget "http://www.marine-geo.org/cgi-bin/getgridB?west=${w}&east=${e}&south=${s}&north=${n}&resolution=1" -O /tmp/test.grd
  r.in.gdal /tmp/test.grd output=GMRT -o
  rm /tmp/test.grd
* Note: Downloaded file contains no projection information, but is EPSG:4326 (WGS84 Geographic).  The file size is limited, but lower resolution (resolution=2,4,8) data can be downloaded for larger areas.
=== Miscellaneous ===
=== Miscellaneous ===

Revision as of 08:00, 3 March 2010

Raster data

ASTER topography

GDEM global 30m elevation calculated from stereo-pair images collected by the Terra satellite. "This is the most complete, consistent global digital elevation data yet made available to the world." This is a very new dataset, at version 1 (treat as experimental). Accuracy will be improved in forthcoming versions (validation with SRTM, etc.; see assessment here and here).

Tutorial: ASTER topography.


Blue Marble imagery

NASA's Blue Marble is a 500m-8 degree per-cell world wide visual image of the Earth from space, with the clouds removed.

Natural Earth imagery

True Marble imagery

  • True Marble: 250m world wide visual image of the Earth from space, with the clouds removed. GeoTIFF (use the r.in.gdal module)


(Earth Observing-1)

  • "Advanced Land Imager (ALI) provides image data from ten spectral bands (band designations). The instrument operates in a pushbroom fashion, with a spatial resolution of 30 meters for the multispectral bands and 10 meters for the panchromatic band."
-- http://eros.usgs.gov/products/satellite/eo1.php
  • On-board Atmospheric Corrections


The ETOPO datasets provide global topography and bathymetry at 1', 2', and 5' per-cell resolutions.


The cell registered version can be loaded directly into a lat/lon region. GRASS raster data is cell registered (see the GRASS raster semantics page)

The grid registered version must be loaded into a simple XY location using the parameters found in the .hdr file, and needs to have the 90deg N,S rows cropped away:

# create a new simple XY location and mapset

# Import grid registered binary float
r.in.bin -f in=etopo1_bed_g.flt out=etopo1_bed_g \
   n=90.008333333335 s=-90.008333333335 e=180.00833333334 \
   w=-180.00833333334 rows=10801 cols=21601 anull=-9999
r.colors out=etopo1_bed_g color=etopo2

# reduce region by 1 cell
g.region rast=etopo1_bed_g
eval `g.region -g`
g.region n=n-$nsres s=s+$nsres e=e-$ewres -p

# save smaller raster and remove original
r.mapcalc "etopo1_bed_g.crop = etopo1_bed_g"
g.remove etopo1_bed_g

# change the location to lat/lon by restarting GRASS
#  in the PERMANENT mapset and running g.setproj
#  or move the entire mapset into a lat/lon location
#  and manually edit the $MAPSET/cellhd/ files (dirty!)


ETOPO2v2 data download



  • The General Bathymetric Chart of the Oceans (original 1' release 2003, new 1' and 30" releases 2008)

r.in.gdal can be used to import the GMT netCDF files directly, or if that doesn't work you can use GMT tools to convert to an old-style native GMT format and import that with r.in.bin.

example: (GEBCO 2003 1' data)
# convert to an old style GMT binary .grd using grdreformat
$ grdreformat 3n24s47w14w.grd 3n24s47w14w_Native.grd=bs

# then import into GRASS,
GRASS> r.in.bin -h -s bytes=2 in=3n24s47w14w_Native.grd out=3n24s47w14w

# and set some nice colors
GRASS> r.colors 3n24s47w14w rules=- << EOF
nv magenta
0% black
-7740 0:0:168
0 84:176:248
0 40:124:0
522 68:148:24
1407 148:228:108
1929 232:228:108
2028 232:228:92
2550 228:160:32
2724 216:116:8
2730 grey
2754 grey
2760 252:252:252
2874 252:252:252
2883 192:192:192
2913 192:192:192
100% 252:252:252

Global Multi-Resolution Topography (GMRT)

 export `g.region -g`
 wget "http://www.marine-geo.org/cgi-bin/getgridB?west=${w}&east=${e}&south=${s}&north=${n}&resolution=1" -O /tmp/test.grd
 r.in.gdal /tmp/test.grd output=GMRT -o
 rm /tmp/test.grd
  • Note: Downloaded file contains no projection information, but is EPSG:4326 (WGS84 Geographic). The file size is limited, but lower resolution (resolution=2,4,8) data can be downloaded for larger areas.


Data sources


  • The r.in.gdal modules may be used to import data of many formats, including GMT netCDF
  • The r.in.bin module may be used to import raw binary files


Since October 1, 2008 all Landsat 7 ETM+ scenes held in the USGS EROS archive are available for download at no charge.

  • Download via the Glovis online search tool (req. Java)
  • Download via the USGS's EarthExplorer interface


  • r.in.gdal - Main import tool for complete multiband scenes
  • r.in.wms - Download data covering current map region via WMS server
  • r.in.onearth - WMS frontend for NASA's OnEarth Global Landsat Mosaic
  • i.landsat.rgb - Color balancing/enhancement tool

See also

  • Processing tips can be found on the LANDSAT wiki page


Pathfinder AVHRR SST

  • see the Pathfinder AVHRR SST wiki page



Smith and Sandwell


Space Shuttle Radar Topography Mission


WorldClim is a set of global climate layers (climate grids) with a spatial resolution of a square kilometer.

OGC WCS - Albedo example

GRASS imports OGC Web Coverage Service data. Example server (please suggest a better one!)


Save this as albedo.xml. Import into a LatLong WGS84 location:

 r.in.gdal albedo.xml out=albedo

Unfortunately this server sends out the map shifted by 0.5 pixel. This requires a fix to the map boundary coordinates:

 r.region albedo n=90 s=-90 w=-180 e=180

Now apply color table and look at the map:

 r.colors albedo color=byr
 d.mon x0
 d.rast albedo


Snow Data Assimilation System data that support hydrologic modeling and analysis. First download the data, and untar them (once for each month, and once for each day), and you should get pairs of “.dat” and “.Hdr” files. The data files are stored in flat 16-bit binary format, so assuming that “snowdas_in.dat” is the name of the input file, at the GRASS prompt:

  r.in.bin -bs bytes=2 rows=3351 cols=6935 north=52.874583333332339 \
  south=24.949583333333454 east=-66.942083333334011 west=-124.733749999998366 \
  anull=-9999 input=snowdas_input.dat output=snowdas

Soviet topographic maps

Vector data

CDC Geographic Boundary and Public Health Maps

Global Administrative Areas

  • GADM is a database of the location of the world's administrative areas (boundaries) available in shapefiles.
http://gadm.org (extracted by country here)
  • World Borders Dataset including ISO 3166-1 Country codes available in shapefiles.
  • Free GIS data from Mapping Hacks

GSHHS World Coastline

GSHHS is a high resolution shoreline dataset. It is derived from data in the public domain and licensed as GPL. The shorelines are constructed entirely from hierarchically arranged closed polygons. It is closely linked to the GMT project.

For GRASS 6 you can download 1:250,000 shoreline data from NOAA's site in Mapgen format, which can be imported with the v.in.mapgen module.


See the OpenStreetMap wiki page.


Second Administrative Level Boundaries: "The SALB dataset is a global digital dataset consisting of digital maps and codes that can be downloaded on a country by country basis."


1:1 million vector data. Formerly known as Digital Chart of the World

See also

National datasets