geojson-equality

Check two valid geojson geometries for equality.

installation

npm install geojson-equality

usage

var GeojsonEquality = require('geojson-equality');
var eq = new GeojsonEquality();
 
var g1 = { "type": "Polygon", "coordinates": [
  [[30, 10], [40, 40], [20, 40], [10, 20], [30, 10]]
]};
var g2 = { "type": "Polygon", "coordinates": [
  [[30, 10], [40, 40], [20, 40], [10, 20], [30, 10]]
]};

eq.compare(g1,g2);    // returns true
var g3 = { "type": "Polygon", "coordinates": [
  [[300, 100], [400, 400], [200, 400], [100, 200], [300, 100]]
]};

eq.compare(g1,g3);    // returns false

For including in browser, download file geojson-equality.min.js

<script type="text/javascipt" src="path/to/geojson-equality.min.js"></script>

This create a global variable 'GeojsonEquality' GeojsonEquality class can be initiated with many options that are used to match the geojson.

• precision number as floating points precision required. Defualt is 17

var g1 = { "type": "Point", "coordinates": [30.2, 10] };
var g2 = { "type": "Point", "coordinates": [30.22233, 10] };
var eq = new GeojsonEquality({precision: 3});
eq.compare(g1,g2);  // returns false
var eq = new GeojsonEquality({precision: 1});
eq.compare(g1,g2);  // returns true

• direction true | false, direction of LineString or Polygon (orientation) is ignored if false. Default is false.

  var g1 = { "type": "LineString", "coordinates": 
    [ [30, 10], [10, 30], [40, 40] ] };
  var g2 = { "type": "LineString", "coordinates": 
    [ [40, 40], [10, 30], [30, 10] ] };
  var eq = new GeojsonEquality({direction: false});
  eq.compare(g1,g2);  // returns true
  var eq = new GeojsonEquality({direction: true});
  eq.compare(g1,g2);  // returns false

• objectComparator function, custom function for use in comparing Feature properties. Default is a shallow comparison.

  // using lodash isEqual to deep comparison
  var isEqual = require('lodash/lang/isEqual')
  var eq = new GeojsonEquality({objectComparator: isEqual});

developing

Once you run

npm install

then for running test

npm run test

to create build

npm run build

license

This project is licensed under the terms of the MIT license.