Viking is a GTK2-based GPS data editor and viewer. It can download and show OpenStreetMaps, Terraserver, and other maps, import and draw tracks and waypoints over them, add coordinate lines, make new tracks and waypoints, hide different things, and more. It uses a hierarchical layering system to organize GPS data, maps, and other layer types with spatial data (such as coordinate lines).
Fimex is a the File Interpolation, Manipulation, and EXtraction library for gridded geospatial data. It converts between different, extensible data formats (currently netcdf, NcML, grib1/2, metgm, wdb, and felt). It enables you to change the projection and interpolation of scalar and vector grids. It makes it possible to subset the gridded data and to extract only parts of the files. For simple usage, Fimex also comes with the command line program fimex.
GRASS (the Geographic Resources Analysis Support System) is a software raster- and vector-based GIS (Geographic Information System), image processing system, graphics production system, and spatial modeling system. It contains many modules for raster data manipulation, vector data manipulation, rendering images on the monitor or paper, multispectral image geocoding and processing, point data management and general data management. It also has tools for interfacing with digitizers, scanners, and the PostgreSQL, DBF, and ODBC connected databases. GRASS operates on all common operating systems.
RoadMap is a navigation program for Unix and PocketPC that displays street maps. Most of the maps are provided by the US Census Bureau, and thus only the US has a decent coverage at this time. A specific area can be displayed by entering a street address (street number, street name, city, and state). It interfaces with a GPS receiver through gpsd or the serial line to track the car position. It has been designed to be usable on a Linux desktop or laptop computer, or on a PDA (Linux or PocketPC).
SaVi is satellite visualization software that lets you create, run, examine, and modify satellite orbits in two and three dimensions. Simulations of Iridium, Globalstar, Galileo, GPS, and other satellite constellations are included. SaVi requires Tcl and Tk on a system with Unix libraries. SaVi works well with the 3D renderer Geomview. Geomview is optional, though recommended for its 3D rendering capabilities.
Engauge Digitizer is digitizing software that converts an image showing a graph or map into numbers. The image file can come from a scanner, digital camera, or screenshot. The numbers can be read on the screen, and written or copied to a spreadsheet. Highlights for beginners include an intuitive interface and extensive context-sensitive documentation. Highlights for experts include compensation for image distortion, cartesian and polar coordinates, linear and logarithmic coordinates, automatic scanning, graphical previews, and browser help.
GPSBabel converts waypoint data between about fifty file formats, including Magellan and Garmin serial, Garmin USB, Mapsource, Mapsend, Streets & Trips, Delorme, National Geographic, many PDA formats, and many others. It is endian and word-size safe, includes a GUI, and runs on a variety of operating systems. It also supports Groundspeak GPX extensions for geocaching.
Mapnik is a toolkit for developing GIS applications. At the core is a C++ shared library providing algorithms/patterns for spatial data access and visualization. Essentially a collection of geographic objects (map, layer, datasource, feature, and geometry), the library doesn't rely on "windowing systems" and can be deployed in any server environment. It is intended to play fair in a multi-threaded environment and is aimed primarily, but not exclusively, at Web-based development. High-level Python bindings (boost.python) facilitate rapid application development, targeting zope3, django, etc.