# Unit 01 - About GRASS GIS¶

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 modelling, and visualization. GRASS GIS is currently used in academic and commercial settings around the world, as well as by many governmental agencies and environmental consulting companies. It is a founding member of the Open Source Geospatial Foundation (OSGeo).

Originally developed by the U.S. Army Construction Engineering Research Laboratories (USA-CERL, 1982-1995, see history of GRASS 1.0-4.2 and 5beta), a branch of the US Army Corp of Engineers, as a tool for land management and environmental planning by the military, GRASS GIS has evolved into a powerful utility with a wide range of applications in many different areas of applications and scientific research (source: https://grass.osgeo.org).

GRASS GIS promo video from 1987

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## In a nutshell¶

• open-source, you can use it freely, modify, improve, share
• a strong user community, commercial support
• large scale functionality, a large amount of tools (2D/3D raster/vector, topology, imagery, map production, spatio-temporal data, …)
• both GUI and CMD (easy for scripting) user interface
• Python API and libraries

• open-source ;-)
• complicated for newcomers (we solved it in GRASS 8 ;-))
• native data format (requires importing data, be aware of the possibility of linking external formats)
• vector topology (confusing for GIS beginners, sometimes tricky to import broken GIS data)

When to use GRASS GIS?

• doing data analysis
• working with topological vector data
• working with a large amount of data
• analysing spatio-temporal data
• doing Python scripting
• deploying server-side applications (see actinia project for example)

When to use rather something else?

• want to visualize geodata in an easy and quick way (use QGIS instead)
• want to access simple features
• being scared of location and mapsets ;-)

## How to install¶

### GNU/Linux¶

Example for Debian/Ubuntu OS:

sudo apt install grass


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