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POSpatial index/query (finding k nearest points)
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2011-05-17T03:40:15.737
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Body
I have +10k points (latitude, longitude) and I'm building an app that shows you the k nearest points to a user's location. I think this is a very common problem and I don't want to reinvent the wheel. I'm learning about Quadtrees. It seems to be a good approach to solve this spatial problem. I'm using these tools: <ul> <li>Python 2.5</li> <li>MySQL</li> <li>MongoDb</li> </ul> Building the Quadtree is not that hard: <a href="http://donar.umiacs.umd.edu/quadtree/points/pointquad.html" rel="nofollow">http://donar.umiacs.umd.edu/quadtree/points/pointquad.html</a> But once I've created the tree and saved it to a db (MySQL or MongoDb), how I run the query? I need to run queries like these: <ol> <li>Find all points within 10 km of the user's location.</li> <li>Find the 6 (or at least 6) nearest points to the user's location.</li> </ol> What's the standard and common approach to do it? EDIT 1: I've loaded the +10k points into MongoDB (Geospatial indexing) and it works fine at first glance. Anyway I've found <a href="http://postgis.refractions.net/" rel="nofollow">PostGis</a>: <blockquote> PostGIS is an extension to the PostgreSQL object-relational database system which allows GIS (Geographic Information Systems) objects to be stored in the database. </blockquote> So I think I'll give PostGis a try. I've also found <a href="https://simplegeo.com/" rel="nofollow">SimpleGeo</a>. You can store points/places in the cloud and then query them via an API: <a href="https://simplegeo.com/docs/tutorials/python#how-do-radial-nearby-query" rel="nofollow">https://simplegeo.com/docs/tutorials/python#how-do-radial-nearby-query</a>
Tags
<python><geospatial><spatial><spatial-index><spatial-query>
Title
Spatial index/query (finding k nearest points)
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