OrbisGIS is a cross-platform open-source Geographic Information System (GIS) created by research and for research. It is developed by the French IRSTV institute and licensed under GPLv3.
It is a complete GIS package. All the basic mapping,editing and presentation can be done with this software.
It includes the features like Multi agent System and Cellular Automata for simulation. It could be useful for ecological and environmental modelling.
It supports the Web Map Service (WMS) and data bases like PostGreSQL,HSQLDB and Post GIS.
It also supports all kind of vector analysis (topology, network and conversion etc.,) and some basic statistics analysis.
It also supports raster analysis like Zonal , Focal, Distance and Global analysis too. (But not supporting interpolation).