SeisSoft
- Producers of projection and datum transform software.
- http://www.connect.net/jbanta/
Decimaldegrees
- Investigation of and experimentation with various GIS technologies, and the Internet. Latitude, longitude conversion and geocoding tools.
- http://www.decimaldegrees.com
CoordTrans
- Convert geographic coordinates between UTM, WGS84, NAD83, NAD27 and other national grids.
- http://franson.biz/coordtrans
ZipMath
- World database with latitude and longitude coordinates. Includes formula for calculating the distance between any two world cities.
- http://www.zipmath.com/world.html