gData, Beta version.
Select and download free geographic (GIS) data for any country in the world
Webpage and datasets under construction! Do send your feedback...

Theme

Country


Sources

Theme Description Source Format Resolution
Administrative areas (boundaries) Country outlines and administrative subdivisions for all countries. The level of subdivision varies between countries GADM Vector (area) -
Inland water Rivers, canals, and lakes. Seperate files for line and area features Digital Chart of the World Vector (line and area) -
Roads Roads Digital Chart of the World Vector (line) -
Railroads Railroads Digital Chart of the World Vector (line) -
Elevation SRTM30 dataset. CGIAR-SRTM data aggregated to 30 seconds CGIAR SRTM (3 seconds resolution) Grid 30 seconds
Land cover Land cover, original data resampled onto a 30 seconds grid GLC2000 Grid 30 seconds
Population Population density (old) xxx Grid 30 seconds
Climate Monthly climate data WorldClim Grid 30 seconds
Gazetteer A gazetteer is a list of place names and their coordinates. The files you can download here are for use in DIVA for automatic georeferencing (to assign coordinates to places). The files should be placed in the \gazet directory. (old, use Biogeomancer). They can also be used to map localities, however you can download more recent files from NIMA U.S. National Imagery and Mapping Agency's (NIMA) database of foreign geographic feature names DBF -

Formats

The files have been compressed and grouped in ZIP files. You can use programs such as 7-zip, PKZIP or StuffIt to decompress the files. Vector data are stored as ESRI shapefiles Grid (raster) data are stored as DIVA gridfiles Each "shapefile" consist of at least three actual files. This is a commonly used format that can be directly used in Arc-anything, DIVA-GIS, and many other programs. It can be imported to most other GIS programs. Shapefiles contain a single class of "vector" data such as points, lines, or polygons. Gridfiles are used in DIVA-GIS. From DIVA-GIS they can be exported to a number of other grid formats including IDRISI and Arc or to shapefiles. (More info on format; for developers). A gridfile with "country mask" indicates that the areas outside the selected country are masked out. For these areas, the value is "NODATA" (indicating the absence of data for those cells). For the other gridfiles, NODATA is only used for areas covered with water, except for the land cover grids, on which water is a separate class. A DBF (dBase file) is a dbase format database table. 

Resolution

The resolution is the size of each grid cell expressed as the length of one side of one (square) cell. The units are in (arc) degrees, minutes or seconds. When the cell size is small (e.g., 30 seconds), resolution is high. The size in square meters varies with latitude. A cell with a 30 seconds resolution is about 0.8 km2  at the equator and smaller at higher latitudes. High resolution files for large areas (countries) can be very large. This means that it may take a while to download these files, and that you will need a fast PC to work with them.
This web page was developed by Robert Hijmans //r.hijmans [a] gmail [dot] com\\ for the BioGeomancer project.
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