Tools for cartography and mapping

DIY ISPs

Celutz: Tool to visualize and geo-reference panoramic photos. Useful to plan line-of-sight wireless links, and approximate the location of potential wireless subscribers. Written in Django.
HeyWhatsThat: Online tool to create coverage maps. Has also http://wisp.heywhatsthat.com/ for LoS calculations.
HeyWhatsThat Path Profiler: Online tool to check the topographic profile between two given points.

LibreMap : nice tool for mapping wireless routers and links, designed for wireless community networks. It has a nice API, integrates well with OpenWRT, supports replicating throughout multiple instances. Code at GitHub.
nodewatcher, an open source network planning, deployment, monitoring and maintenance platform with emphasis on community. Provides also mapping module.
Nodeshot: born out of Ninux.org, it allow users to map geographical data, contact one another and stay up to date with what happens in the community. A live instance of the new development version can be seen at https://test.map.ninux.org/
WiND: WiND is a Web application targeting at Wireless Community Networks. It was created as a replacement for NodeDB by the members of Athens Wireless Metropolitan Network (AWMN) located in Athens, Greece. A live instance can be seen at AWMN and at Sarantaporo.gr Community Network