According to Dave Troy, Google seems to be using the Geohash algorithm:
Google is employing the GeoHash algorithm I’ve been pushing to do spatial searching using BigTable. Since database schemes like BigTable don’t support traditional GIS extensions/spatial indexes, GeoHash allows for a simple bounding box search using truncated GeoHash substrings. I will post separately about this shortly, as I am working on some GeoHash tools to expand this functionality. This is of particular interest to AppEngine developers.
Nice!
Wow, this blew my mind — don’t you think it’s fantastic when people use something you built in a way you never foresaw?
Congratulations!
Awesome. Must be really exciting to see that Google and xkcd are using/talking about something you invented.
Congratulations!
Best Regards
Leandro Lameiro
http://lameiro.wordpress.com/
Congratulations!!
Awesome! Well done :)
Awesome! Congrats!
Gustavo,
Your alg. is refreshingly elegant. I was interested in Locapoint, but that one is licensed commercialy. I’m hoping it becomes a defacto URL standard for places.
Taylor
Hi I’m a fan of your Geohash but I have a simple idea to shorten the code further and thus make it easy to remember the problem is that your base location is the world and thus your starting point is too wide an area.
For day to day use it can be a much smaller hash for example I am in Ireland which means i am within an area thats probably a range of 4 degrees of longitude and 6 degree’s of latitude. This is a much smaller area to define. Thus knowing Im in ireland you can refine the geohash and assume the initial significant figures and then use a shorter string and be as accurate.
So what I’m suggesting is you can prepare look up tables for each country or state and then prepare a geohash minus the offsets for that country. obviously you could go further and define area’s even smaller.
probably the easiest way to define a country area is to define an area as something like ireland is a country contained within a bounding box of between 50 and 54 degrees north and between 5 and 9 degrees west. and the base offset would be 50 north and 5 west.