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QGIS


written by Grant Hamilton



Basic Information Name: QGIS
Acronym/Other Names: Formerly known as Quantum GIS
Author/Owner/Steward: Open Source Geospatial Foundation
Type: Free, open source standalone program
Platform: Windows, Mac, Linux, BSD, Android (Beta)
Download: http://www.qgis.org/en/site/forusers/download.html

Description

QGIS is a free and open source GIS program developed by a team volunteers with the support of non-profit organizations. It utilizes a graphical user interface. It is compatible with a variety of operating systems and is available in 32-bit and 64-bit versions. Users of ESRI software will find that many of the features and tools of ArcMap are also available in QGIS. The interface of QGIS is similar to ArcMap. For users of ESRI products, QGIS is a good way to explore open source GIS software.

Features

  • QGIS supports many file formats from a variety of vendors including ESRI shapefiles, raster formats (including GeoTiff, Erdas Img., ArcInfo Ascii Grid, JPEG, PNG), Geographic Resources Analysis Support System (GRASS) vector and raster files, and server-based files (e.g. WMS).
  • OpenStreet maps can be viewed and edited.
  • GPX GPS files are supported.
  • Users can share data on the Web by uploading it to a server (WMS and WFS supported).
  • Numerous plugins are available; any plugin compatible with GRASS will also work with QGIS.
  • Scripting is accomplished through a Python console.
  • Create publishable quality maps with symbology editing.

Screenshots

Viewing a shapefile's attribute table.

A DEM in QGIS. 10m contour intervals were created using the Extraction Tool.

Raster Calculator. A query of the DEM for pixels with an elevation of 950m or greater was performed.

Tools

A selection of tools available in QGIS follows:

Vector

  • Spatial Query
  • Nearest Neighbor Analysis
  • Analysis Tools (Union, Clip, Buffer, Intersect, etc.)
  • Geometry Tools (Polygon Centroids, Delauney Triangulation, Polygon to Lines/Lines to Polygon, etc.)
  • Data Management Tools (Define Projection, Join, Split, Merge)
  • GPS Tools - Convert to GPX file

Raster

  • Raster Calculator (similar to Map Algebra in ArcMap; uses SQL syntax to perform queries)
  • Interpolation using Inverse Distance Weighting (IDW) or Triangular Irregular Network (TIN)
  • Terrain Analysis (Slope, Aspect, Ruggedness Index, Hillshade, Relief)
  • Zonal Statistics - calculates sum, mean value, or total count in a raster layer when using a vector layer to delineate zones
  • Conversion (Polygon to Raster/Raster to Polygon)
  • Extraction (Contour Intervals)
  • Build Pyramids

Spatial Databases

QGIS does not support ESRI personal or file geodatabases. In order to open a feature class, it will have to first be converted to a shapefile. Rasters from geodatabases will also have to be converted. QGIS does support PostGIS and SpatialLite databases, both of which are based on SQL. PostGIS and Spatial are free open source spatial database management programs.

QGIS: A free and open source Geographic Information System - http://www.qgis.org/en/site/index.html

  • QGIS homepage

Quantum GIS Planet - http://planet.qgis.org/planet/

  • The official QGIS blog

Contact Information

Discussion/Comments

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tools/qgis.txt · Last modified: 2013/11/04 19:17 by jgh