GRASS GIS, commonly referred to as GRASS (Geographic Resources Analysis Support System), is a free and open source Geographic Information System (GIS) software suite used for geospatial data management and analysis, image processing, graphics and maps production, spatial modeling, and visualization.

The GRASS GIS project is an international team effort with scientists and developers participating from various fields. GRASS – Geographic Resources Analysis Support System has been under continual development since 1982 and has involved a large number of federal US agencies, universities, and private companies. The core components of GRASS and the management of the integration of the efforts into GRASS releases were accomplished by the Construction Engineering Resesarch Laboratory (CERL) in Champaign, Illinois. It has been estimated that several million dollars of GRASS GIS software development efforts across the government have been completed since the 4.1 release. Since 1997 a worldwide network of developers continue to release new GRASS GIS versions (see GRASS history).

The strength and success of GRASS GIS relies on the user community. With this in mind, the philosophy of the GRASS Development Team is to encourage users to develop their own unique tools and applications for GRASS. Many people have contributed to the GRASS GIS. As GRASS GIS is growing, we have plenty of opportunities to join the GRASS development team and improve the powerful GRASS GIS under terms of GNU General Public License.

Core features

  • Analysis

    • Raster: map algebra, interpolation, mask, solar analysis, landscape structure
    • Vector: network analysis, buffer, overlays, point cloud data
    • Temporal: big time series data management and temporal analysis
    • Image processing: aerial and UAV image, satellite data, supervised, unsupervised, and object classification
    • Terrain analysis: contour and surface generation, least cost path, slope and aspect analysis
    • Hydrology: flow directions, streams, watersheds (basins), topographic index
    • Point cloud analysis: LiDAR, interpolation, binning, vegetation metrics
    • 3D raster (voxel) analysis: 3D map algebra, 3D interpolation, 3D visualization
    • Spatial statistics: correlation and covariance analysis, regression
    • Geocoding: raster and vector maps
  • Interfaces

    • Graphical user interface (GUI) for new users and interactive analysis
    • Command line interface (CLI) for power users and text-based environments
    • Python scripting library
    • Object-oriented Python API
    • C API
    • Generic XML and WPS description of every module
  • Third-party interfaces

    • QGIS has two different ways to run GRASS GIS modules
    • Web interface through WPS servers
    • R has an interface to GRAS GIS, called rgrass7
    • JGrasstools for Java
    • Ruby also has an interface called grassgis
  • Open science ready

    • Publishing algorithms through GRASS GIS
    • Longetivity, preservation, and maintenance of the code
    • References to papers listed in the documetation
    • Source code linked from documentation
    • Algorithms created by scientists for scientists
    • Interfaces and APIs addressing needs of different scientists
    • Distribution of binaries for different platforms

Implemented Standards

  • Geographic JSON (GeoJSON)
  • Georeferenced Tagged Image File Format (GeoTIFF)
  • OpenStreetMap (OSM)
  • Web Map Service (WMS)
  • Web Processing Service (WPS)
GRASS GIS graphical user interface

Service Providers

Core contributors

View all service providers