Quantum GIS (QGIS) is a user friendly Geographic Information System
that runs on Linux, Unix, Mac OSX, and Windows.  QGIS lets you 
browse and create map data on your computer.  It supports many 
common spatial data formats (e.g. ESRI ShapeFile, geotiff).

The following packages are required by qgis: proj, geos, gdal, R,
gsl and numpy. Optional dependencies include postgresql, postgis
and gpsbabel. All these packages are available at SlackBuilds.org.

The Quantum GIS homepage is at http://qgis.org/