ESRI's GIS (geographic information systems) mapping software helps you understand and visualize data to make decisions based on the best information and analysis.
Opticks is an expandable remote sensing and imagery analysis software platform that is free and open source. If you've used other commercial tools like: ERDAS IMAGINE, RemoteView, ENVI, or SOCET GXP, then you need to give Opticks a try. Unlike other competing tools, you can add capability to Opticks by creating an extension. Opticks provides the most advanced extension capability of any other remote sensing tool on the market.
a C++ port of the Java Topology Suite (JTS). As such, it aims to contain the complete functionality of JTS in C++. This includes all the OpenGIS "Simple Features for SQL" spatial predicate functions and spatial operators, as well as specific JTS topology
Natural Earth is a public domain map dataset available at 1:10m, 1:50m, and 1:110 million scales. Featuring tightly integrated vector and raster data, with Natural Earth you can make a variety of visually pleasing, well-crafted maps with cartography or GIS software.
Project Detail - Digital Preservation (Library of Congress). The GeoMAPP project is exploring ways to expand the capabilities of state governments to provide long-term access to geospatial data. The project is bringing together geospatial and archival staff in multiple states to identify, preserve, and make available temporal and superseded digital geospatial data with ongoing value. A key approach will include testing a geographically dispersed content-exchange network for the replication of state and local geospatial data among several states to promote preservation and access.
OpenLayers is a pure JavaScript library for displaying map data in most modern web browsers, with no server-side dependencies. OpenLayers implements a (still-developing) JavaScript API for building rich web-based geographic applications, similar to the Go
The Open Geospatial Consortium, Inc.® (OGC) is a non-profit, international, voluntary consensus standards organization that is leading the development of standards for geospatial and location based services.