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5
votes
1answer
71 views

Algorithm to find N nearest points to point

My situation is that i'm trying to build a mobile app, and find the x number of points closest to a users location that satisfy certain conditions that the user chooses on the front end. My current ...
2
votes
1answer
32 views

How to query a JTS QuadTree using a query envelope with holes

Hi I have a Java Topology Suite QuadTree containing Points, now I'm trying to query the QuadTree with a polygon that contains a hole. Here's how I create the polygon. //Method will create a ...
0
votes
0answers
22 views

php array of s2 map indexes to quadtree array

i have a list of s2map cells (at various levels) that i wish to convert to a quadtree for easy-er processing as shown here in binary ...
1
vote
0answers
66 views

Creating quadtree index on latitude, longitude data in PostGIS

I have a table of locations in which one of the columns represents the lat-long for the location. These coordinates have been extracted from the OpenStreetMap file. How can I create a quadtree index ...
4
votes
1answer
316 views

Are there trade offs between using a geohash vs using a quadkey as a spatial index?

QuadKey Bing Maps uses a quadkey structure for their tiling scheme. Here is an overview of the concept http://msdn.microsoft.com/en-us/library/bb259689.aspx. GeoHash A geohash seems to be the more ...
1
vote
0answers
206 views

Can I get a list of points in a polygon using Quadtrees?

I'm storing vertices in a PR (or PM if needed) quadtree and would like to be able to: Find out if a given polygon contains at least one point Optionally: Get a list of all the points within a ...
2
votes
0answers
191 views

Tree structure for a muticolored region quadtree

Is a B+ tree suitable for a multicolored region quadtree (for example, one segmenting a plot of land into several crops)? I recently purchased a copy of Samet's 'Foundations of Multidimensional and ...
14
votes
4answers
2k views

How can I generate irregular grid containing minimum n points?

Given a large (~ 1 million) sample of unevenly distributed points - is it possible to generate irregular grid (in size, but could also be irregular in shape if that is possible?) that will contain ...
1
vote
0answers
64 views

trim a global quadtree by population density?

I'm looking for a way to match people so as to find other members that are 'nearby' - not for those dreadful 'girls near you' ads, don't worry ;_) Of course 'nearby' in the country is a different ...