How do I query for entities that are "nearby" with the GeoPt property in Google App Engine?

Question

How should I create a GQL query that returns the nearest entities (from my current location) based on their GeoPt property? Should I just created a 'distance' function that calculates for a set of entities with a reasonably close distance?

Thanks ahead of time!

Answer 1

App Engine doesn't treat GeoPt properties specially - it has no built in spatial indexing. There are a number of third-party libraries that add support for spatial indexing, however. The best one (in my opinion) being geomodel.

Answer 2

You could store the locations in App Engine in a Quadtree structure.

Here's one description of how it would be done: Geographic Queries on Google App Engine