![]() This means that it may take a while to download these files, and that you will need a fast PC to work with them. High resolution files for large areas (countries) can be very large. A common practice when dealing with raster files is to clip the raster so. A cell with a 30 seconds resolution is about 0.8 km2 at the equator and smaller at higher latitudes. The larger the raster file the longer it will take to load into a GIS program. The size in square meters varies with latitude. When the cell size is small (e.g., 30 seconds), resolution is high. The units are in (arc) degrees, minutes or seconds. The resolution is the size of each grid cell expressed as the length of one side of one (square) cell. 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.Ī DBF (dBase file) is a dbase format database table. For these areas, the value is "NODATA" (indicating the absence of data for those cells). ( More info on format for developers).Ī gridfile with "country mask" indicates that the areas outside the selected country are masked out. From DIVA-GIS they can be exported to a number of other grid formats including IDRISI and Arc or to shapefiles. Shapefiles contain a single class of "vector" data such as points, lines, or polygons. It can be imported to most other GIS programs. There are numerous formats available for both raster and vector data. This is a commonly used format that can be directly used in Arc-anything, DIVA-GIS, and many other programs. Raster and vector data are stored in different formats. The geodatabase is a collection of various types of GIS datasets held in a file system folder. Grid (raster) data are stored as DIVA gridfilesĮach "shapefile" consist of at least three actual files. The geodatabase is the native data structure for ArcGIS and is the primary data format for representing and managing geographic information, including raster datasets and mosaic datasets. Vector data are stored as ESRI shapefiles This file format is faster, supports larger rasters, and. You can use programs such as 7-zip, PKZIP or StuffIt to decompress the files. IMG or Imagine files are the preferred raster file format to use with ArcGIS and other Esri products. The files have been compressed and grouped in ZIP files. National Imagery and Mapping Agency's (NIMA) database of foreign geographic feature names They can also be used to map localities, however you can download more recent files from NIMA There are two main ways to export or convert raster data to another format: using the Export Raster pane or the Copy Raster geoprocessing tool. The files should be placed in the \gazet directory. The files you can download here are for use in DIVA for automatic georeferencing (to assign coordinates to places). Global gridded population databaseĪ gazetteer is a list of place names and their coordinates. Land cover, original data resampled onto a 30 seconds gridĬIESIN, 2000. Seperate files for line and area features The level of subdivision varies between countries ![]() ![]() ![]() Select and download free geographic (GIS) data for any country in the worldĬountry outlines and administrative subdivisions for all countries. ![]()
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