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chncrs

0.1.6 • Public • Published

Chinese Coordinate Transform

Coordinate or GeoJSON trasnforming from WGS84 to various encrypted Chinese coordinate systems such as BD09LL, GCJ02 and vice versa.

Supported coordinate reference systems (CRS)

  • GCJ02 : Chinese encrypted coordinate system
  • BD09LL : CRS used by http://map.baidu.com
  • WGS84 : well-known CRS, aka EPSG:4326

Definition

convertor.transform(source, fromCRS, toCRS);
  • source : a coordinate, array of coordinates, a GeoJSON or a array of GeoJSON to transform, possible values:
    • a coordinate: [x, y]
    • coordinate arrays: [[x1,y1], [x2, y2]] or more dimensions: [[[x1,y1], [x2, y2], [x3, y3]]]
    • a geoJSON object: { "type": "Point", "coordinates": [100.0, 0.0] }
    • a array of geoJSON objects: [{ "type": "Point", "coordinates": [100.0, 0.0] } , { "type": "Point", "coordinates": [101.0, 1.0] }]
  • fromCRS : CRS transform from, possble values:
    • 'gcj02'
    • 'bd09ll'
    • 'wgs84' | 'EPSG:4326'
  • toCRS : CRS transform to, same possible values with fromCRS

How to use

Node

    npm install chncrs

Browser

    <script src="chncrs.js"></script> 
    <script type="text/javascript">
        var c = maptalks.CRSTransform.transform([114.68837663801743, 33.63312016454496], 'GCJ02', 'BD09LL');
    </script> 

Example

    var convertor = require('chncrs');
    //convert coordinates from gcj02 to bd09ll
    var c = convertor.transform([114.68837663801743, 33.63312016454496], 'GCJ02', 'BD09LL');
    
    //convert a geoJSON object from gcj02 to bd09ll
    //can also be other geometry type, a Feature, even a FeatureCollection
    var geo = { "type": "Point", "coordinates": [100.0, 0.0] };
    var geo2 = convertor.transform(geo, 'GCJ02', 'BD09LL');
 
    
    //a geoJSON array
    var geos = [{ "type": "Point", "coordinates": [100.0, 0.0] } ,
                { "type": "Point", "coordinates": [101.0, 1.0] }];
    var geos2 = convertor.transform(geo, 'GCJ02', 'BD09LL');
    
    //a Feature
    var feature = { "type": "Feature",
              "geometry": {"type": "Point", "coordinates": [102.0, 0.5]},
              "properties": {"prop0": "value0"}
            };
    var feature2 = convertor.transform(geo, 'GCJ02', 'BD09LL');
 
    //a FeatureCollection
    var featureCollection = {
                "type": "FeatureCollection",
                "features": [
                    { "type": "Feature",
                      "geometry": {"type": "Point", "coordinates": [102.0, 0.5]},
                      "properties": {"prop0": "value0"}
                    },
                    { "type": "Feature",
                      "geometry": {
                          "type": "LineString",
                          "coordinates": [
                              [102.0, 0.0], [103.0, 1.0], [104.0, 0.0], [105.0, 1.0]
                          ]
                      }
                 ]
              };
    var featureCollection2 = convertor.transform(geo, 'GCJ02', 'BD09LL');

Readme

Keywords

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Install

npm i chncrs

Repository

github.com/FuZhenn/chinese_coordinate_conversion

Homepage

github.com/FuZhenn/chinese_coordinate_conversion#readme

Weekly Downloads

57

Version

0.1.6

License

WTFPL

Last publish

Collaborators

  • fuzhenn
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