https://github.com/armon/erl-rstar

An Erlang implementation of the R*-tree spacial data structure
https://github.com/armon/erl-rstar

Last synced: about 2 months ago
JSON representation

An Erlang implementation of the R*-tree spacial data structure

• Host: GitHub
• URL: https://github.com/armon/erl-rstar
• Owner: armon
• License: other
• Created: 2012-11-17T00:31:35.000Z (about 12 years ago)
• Default Branch: master
• Last Pushed: 2018-07-11T00:56:37.000Z (over 6 years ago)
• Last Synced: 2024-08-04T01:15:22.794Z (4 months ago)
• Language: Erlang
• Size: 301 KB
• Stars: 59
• Watchers: 7
• Forks: 19
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• beamtoolbox - [erl
• awesome-erlang - erl-rstar - An Erlang implementation of the R*-tree spacial data structure. (Geolocation)

README

        
Erlang Rstar [![Build Status](https://travis-ci.org/armon/erl-rstar.png)](https://travis-ci.org/armon/erl-rstar)

=========

This application provides a pure Erlang implementation of the R*-tree

data structure. The R*-tree structure is particularly suited for indexing

multi-dimensional data, with relatively low dimensionality. It is a commonly

used data structure for geo-spacial data for this reason. In addition to

efficiently supporting window queries, it can also quickly find the nearest

neighbors of a point.

This implementation is in-memory only and does not provide builtin support

for disk-backed usaged.

Modules

-----

* rstar : The primary top level module used to manipulate the tree

* rstar_geometry : Used to modify the geometry type associated with trees

* rstar_util: Contains a various utility methods that may be useful

Usage

-----

Below are some examples of usage.

Simple creation of trees and population of points:

    % Creates a two dimensional R-tree

    Tree = rstar:new(2),

    % Create a point, at X:1, Y:3, opaque value foo

    Point = rstar_geometry:point2d(1, 3, foo),

    % Insert into the tree, returning a new tree

    T2 = rstar:insert(Tree, Point),

    % Delete the point

    T3 = rstar:delete(T2, Point).

Creating various geometries:

    % Create a 2D box from the origin to 2,2

    Box = rstar_geometry:new(2, [{0, 2}, {0, 2}], small_box),

    % Create a 3D box

    Box3D = rstar_geometry:new(3, [{2, 3}, {2, 3}, {2, 3}], three_d_box),

    % Create a 3D point

    Point3D = rstar_geometry:point3d(0, 1, 2, point3d),

    % Create a 4D point at the origin

    Origin4D = rstar_geometry:origin(4).

Various queries:

    % Create a tree and populate it

    T = rstar:new(2),

    ....

    TFinal = rstar:insert(...),

    % Do box query

    Box = rstar_geometry:new(2, [{0, 2}, {0, 2}], small_box),

    Matching = rstar:search_within(TFinal, Box),

    % Do a circular query around a point within a distance of 10 units

    % Distance is Euclidean distance

    Point = rstar_geometry:point2d(1, 3, undefined),

    Matching = rstar:search_around(TFinal, Point, 10.0),

    % Find the nearest 20 points

    Matching = rstar:search_nearest(TFinal, Point, 20),

Dependencies

------------

Requires Erlang 18.0 or higher.

References

----------

Related works:

* [R-trees: A dynamic index structure for spacial searching](http://www.cs.jhu.edu/~misha/ReadingSeminar/Papers/Guttman84.pdf)

* [The R*-tree: An Efficient and Robust Access Method for Points and Rectangles](http://www.cs.ucr.edu/~tsotras/cs236/F11/rstar.pdf)

* [Nearest Neighbor Queries](http://postgis.refractions.net/support/nearestneighbor.pdf)

* [Enhanced Nearest Neighbor Search on the R-tree](http://www.cse.cuhk.edu.hk/~adafu/Pub/rtree.ps)