QGIS
gVSIG
Whitebox GAT
SAGA GIS
GRASS GIS
MapWindow
ILWIS (download)
ILWIS (52north)
GeoDa
uDig
OpenJump
Diva GIS
Falconview
OrbisGIS
Google Earth Pro
ArcGIS Earth
MARPLOT
HAZUS
LibreCAD
Tatuk GIS
Opticks
Kalypso
Capaware
Terraview
FLOWMAP
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PathAway programs
GMT
TNTLite
MapCruncher
MapMaker
OSSIM
SPRING
AGIS
KIDS
KOSMO
GISClient
InterIMAGE