Questions tagged [quadtree]

a quadtree is a tree data structure in which each internal node has exactly four children.

Filter by
Sorted by
Tagged with
0
votes
0answers
48 views

Quadtree based polygon indexing? (Python/Java)

I was wondering how to best represent the inside of any given polygon (GeoJSON coordinates) with some sort of indexing, like a grid or quadtree? See image below for an approximation of what I have in ...
3
votes
2answers
245 views

Is there a Java API for in-memory geo indexes?

My application is backed by PostGIS. There is a particular set of tables which have one of their columns being a geographic polygon. They are relatively small in size (few thousand rows) and can ...
1
vote
0answers
39 views

Retrieve all points within a given radius using quadkeys

I'm new to GIS concepts and I'm learning about quadkeys and usage. I am inserting few points with its quadkey into DB, and want to retrieve all points within a given radius using quadkeys. Assume ...
1
vote
0answers
217 views

Use QuadTree in R to create Geospatial clusters [closed]

I am currently looking into different clustering techniques to form clusters from geospatial data. Is it possible to utilize quadtrees(from the SearchTrees package in R) to come up with something ...
4
votes
2answers
679 views

How can I convert Bing's “quadtree” tile addresses to ZXY tile addresses in Python?

Bing uses a quadtree-based addressing scheme to come up with a single number (or all-digit string) as the address of a tile. Each digit/character (starting from left / most significant) identifies the ...
0
votes
1answer
216 views

Use QuadTree for better complexity on search features

I want to improve the complexity of search specific feature when using this function : map.forEachFeatureAtPixel(e.pixel, function (feature, layer) { // Do something.. }); The improvment ...
0
votes
2answers
1k views

Using Bing Maps Quadkeys as Openlayers 3 Tile source

I have a number of tile sources which utilise Bing Maps' Quadkey system in an old Silverlight application and I would like to use them in a new Openlayers 3 map. I have found several examples of ...
6
votes
1answer
4k views

Finding N nearest points to point using JTS?

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 solution is to ...
2
votes
1answer
1k views

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

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 searchable ...
1
vote
0answers
1k 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 ...
8
votes
2answers
2k 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
549 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 given ...
2
votes
0answers
274 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 ...
19
votes
4answers
4k 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
111 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 ...