Hi, There is a description about a GeoBox algorithm & some python source code located here -
http://code.google.com/appengine/articles/geosearch.html Regards On Sep 4, 6:42 am, String <[email protected]> wrote: > This is a common problem in GIS. I'd suggest doing a simple check for > whether each point is within a simple lat/lon box - that should be > fast enough with only 400 points, and should narrow down the list > enough to be able to check the distance on just those few. > > If you're doing this a lot, put the data in SQLite with indexes on lat > & lon; that way you can do this initial "box" query easily & > efficiently. > > String > > Martijn van der Plaat wrote: > > > Dear all, > > > In my application I have a list of +400 GPS coordinates which I > > retrieve from addresses. The application should give me the top X > > nearest coordinates based on my current location. > > > This application is possible (I think) with the distanceBetween > > function. But (I think) the application is really inefficient when i > > iterate through the list of 400 coordinates and check the distance > > within a certain time interval. > > Another option is (I think) the proximityAlert function? All > > coordinates are loaded in this function and when my current location > > comes in the radius of a coordinate an alert is given. But the > > downside of this solution (I think) is the high memory usage which > > implies a short battery life of the Android phone? > > > Please can anybody help me to make the right decision? > > > Greets, > > Martijn --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~----------~----~----~----~------~----~------~--~---
