QGIS

A fully featured, user friendly, open source Geographic Information System (GIS) with similar power to ArcGIS and MapInfo.

Free Open Source Mac OS X Windows Linux Android BSD

GRASS GIS

GRASS GIS (Geographic Resources Analysis Support System) is an open source, free software (FOSS) Geographical Information System (GIS) with raster, topological, vector, image processing, and visualization functionality.

Free Open Source Mac OS X Windows Linux

SAGA GIS

SAGA - System for Automated Geoscientific Analyses - is a Geographic Information System (GIS) software with immense capabilities for geodata processing and analysis....

Free Open Source Mac OS X Windows Linux

Spatial Feature Server

Spatial Feature Server by MapET is an ESRI Geoservices REST Implementation and works with all ESRI Rest API's.

Commercial Windows

what3words

Geocoding system for the simple communication of locations with a resolution of 3 m.

Free Android iPhone iPad Web