node-quadtree


Description

Quadtree is a node module that encodes and decodes geospatial quadtrees.

The encoding algorithm orders the tiles using the bing maps ordering shown below:

!Quadtree ordering

Installation

$ npm install quadtree

Usage

var quadtree = require('quadtree');

var coordinate = {
lat: -27.093364,
lng: -109.367523
};

var precision = 8;
var encoded = quadtree.encode(coordinate, precision); // returns "20310230")

var decoded = quadtree.decode(encoded); // returns { origin: { lng: -108.984375, lat: -27.0703125 }, error: { lng: 0.703125, lat: 0.3515625 } }

var neighbour = quadtree.neighbour(encoded, 1, 1); // returns "20310213"

var boundingBox = quadtree.bbox(encoded); // returns { minlng: -109.6875, minlat: -27.421875, maxlng: -108.28125, maxlat: -26.71875 }

var enveloped = quadtree.envelop(boundingBox, precision); // returns [ '20310230', '20310231', '20310212', '20310213' ]

$3

Encodes a coordinate into a quadtree of the specified precision.

$3

Decodes a quadtree into an origin and error.

$3

Finds the neighbour of the given quadtree, walking a number of tiles in the supplied direction.

$3

Returns the bounding box of the tile containing the supplied quadtree.

$3

Returns an array of quadtrees that are enveloped by the bbox at the supplied precision.

Contributors

Pair programmed by Roy Lines and James Bloomer.