In Memory database that supports Spatial Query

Question

I am trying to solve the problem of "Find point of interest near you" in java. i.e. I have a number of lat,lots of points of interst. And I want to find the ones within say 800 meters. Assuming I know my current lat and log.

My problem is this application has to be stand alone. So I cannot rely on a spatial database query to find the results e.g. using mysql I have found this to be useful: http://xebee.xebia.in/2010/10/28/working-with-geolocations/

Currently I cannot find an in memeory db that supports spatital queries. I was going to resort to using an R-Tree something like http://jsi.sourceforge.net/

But I know that won't be as correct giving the fact it uses a rectange rather than a ciricular search.

Any have any recommendations?

Answer 1

There is an In-Memory Database named Altibase which supports Spatial features. It observes OGC specification. You may make use of it.

Answer 2

Actually the jsi library (http://jsi.sourceforge.net) is pretty much perfect for this problem. It was written to support this exact scenario.

When searching for nearby rectangles (or points) you can supply a maximum distance, and it will return the results in order of increasing distance.

It doesn't support the query "return every point within radius of 800m", but in practice you'll want a limit. So the jsi library does support the more useful "return the nearest 50 points within a radius of 800m".

If you really do want every point within a radius, you can increase the number of points to a large number and run a nearestN query, or do an intersection query and filter by distance in your own code.