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.
Kismet is an 802.11 layer 2 wireless network detector, sniffer, and intrusion detection system. It will work with any wireless card which supports raw monitoring (rfmon) mode, and can sniff 802.11b, 802.11a, 802.11g, and 802.11n traffic (device drivers permitting). It identifies networks by passively collecting packets and detecting standard named networks, detecting (and given time, decloaking) hidden networks, and inferring the presence of non-beaconing networks via data traffic.
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).
Open2300 is a package of software tools that reads (and writes) data from a Lacrosse WS2300, WS2305, WS2310, or WS2315 Weather Station. It includes tools that save data to logfiles, XML files, and MySQL databases, as well as tools that upload your weather data to Weather Underground or Citizen Weather. You can control the display backlight, reset min/max values, and read and write to any memory location. It includes a function library for your own programs and a number of small PHP programs.
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.