GeoServer!

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. Used for geospatial data management and analysis, image processing, graphics/maps production, spatial modeling, and visualization, GRASS is currently used in academic and commercial settings around the world, as well as by many governmental agencies and environmental consulting companies. »

MapBox makes it easy to design beautiful custom maps, and fast to integrate them into websites and mobile applications using Open Street Map data.

Mapnik is a Free Toolkit for developing mapping applications. Above all Mapnik is about making beautiful maps. It is easily extensible and suitable for both desktop and web development. - C++/Python GIS toolkit

SAGA - System for Automated Geoscientific Analyses - is a Geographic Information System (GIS) software with immense capabilities for geodata processing and analysis. SAGA is programmed in the object oriented C++ language and supports the implementation of new functions with a very effective Application Programming Interface (API). Functions are organised as modules in framework independent Module Libraries and can be accessed via SAGA’s Graphical User Interface (GUI) or various scripting environments (shell scripts, Python, R, ...). »

uDig is a GIS software program produced by a community led by Canadian-based consulting company Refractions Research. It is based on the Eclipse platform and features full layered open source GIS. It is written in Java and released under GNU Lesser General Public License.

Esri Geoportal Server is a free open source product that enables discovery and use of geospatial resources including datasets, rasters, and Web services.

The Géoclip interactive mapping solution is proposed by EMC3. Géoclip permits to publish online thematic atlas or territorial observatories. Géoclip allows you to build web mapping applications for cartographic representations of statistical data.

The Map Kit framework provides an interface for embedding maps directly into your own windows and views. This framework also provides support for annotating the map, adding overlays, and performing reverse-geocoding lookups to determine placemark information for a given map coordinate.

Beautiful, User Friendly online mapping software that scales to big data.

MapServer is an Open Source platform for publishing spatial data and interactive mapping applications to the web. Originally developed in the mid-1990’s at the University of Minnesota, MapServer is released under an MIT-style license, and runs on all major platforms (Windows, Linux, Mac OS X).

Innovative Cloud Based mapping tool GeniusGIS is an online sales territory mapping and retail mapping software. Get average daily traffic counts for U.S