SlackBuildsOrg/gis/qgis

Quantum GIS (QGIS) is a user friendly Geographic Information System
that lets you view and manipulate spatial data on your computer.  It 
supports many common spatial data formats (e.g. PostGIS, ShapeFile and
geotiff).

Optional compile-time dependencies: 
 - postgresql and postgis: for PostGIS support
 - gpsbabel: for the GPS plugin
 - grass: for the Grass plugin
 - gsl: for georeferencing support
 - fcgi: for the QGIS server (see README.server)

Optional run-time dependencies:
 - OTB
 - R
 - saga-gis
 - TauDEM

All dependencies must be built with Python 3 support and qtkeychain must be
built after Qt5.