Turn your geo data into GeoJSON.
For node, use npm: $ npm install geojson
In the browser, include geojson.min.js. For example: <script type="text/javascript" src="js/geojson.min.js"></script>
In node, var GeoJSON = require('geojson');
In the browser, the library is available at GeoJSON.
The library has one method, parse, which takes an array of objects (or a single object) with geometry data as the first parameter, an object consisting of settings for the second parameter, and an optional callback function as the third parameter. If a callback is not specified, the parse function returns the GeoJSON output.
Take the example data below:
var data = [
{ name: 'Location A', category: 'Store', street: 'Market', lat: 39.984, lng: -75.343 },
{ name: 'Location B', category: 'House', street: 'Broad', lat: 39.284, lng: -75.833 },
{ name: 'Location C', category: 'Office', street: 'South', lat: 39.123, lng: -74.534 }
];Convert it to GeoJSON:
GeoJSON.parse(data, {Point: ['lat', 'lng']});
{
"type": "FeatureCollection",
"features": [
{ "type": "Feature",
"geometry": {"type": "Point", "coordinates": [-75.343, 39.984]},
"properties": {
"name": "Location A",
"category": "Store"
}
},
{ "type": "Feature",
"geometry": {"type": "Point", "coordinates": [-75.833, 39.284]},
"properties": {
"name": "Location B",
"category": "House"
}
},
{ "type": "Feature",
"geometry": {"type": "Point", "coordinates": [ -75.534, 39.123]},
"properties": {
"name": "Location C",
"category": "Office"
}
}
]
}Convert the example data to GeoJSON, and only include the name attribute in properties for each feature.
GeoJSON.parse(data, {Point: ['lat', 'lng'], include: ['name']});
{
"type": "FeatureCollection",
"features": [
{ "type": "Feature",
"geometry": {"type": "Point", "coordinates": [-75.343, 39.984]},
"properties": {
"name": "Location A"
}
},
...
{ "type": "Feature",
"geometry": {"type": "Point", "coordinates": [ -75.534, 39.123]},
"properties": {
"name": "Location C"
}
}
]
}You can also convert a single object to a GeoJSON feature:
var singleobject = { name: 'Location A', category: 'Store', street: 'Market', lat: 39.984, lng: -75.343 }
GeoJSON.parse(singleobject, {Point: ['lat', 'lng']});
{
"type": "Feature",
"geometry": {"type": "Point", "coordinates": [-75.343, 39.984]},
"properties": {
"name": "Location A",
"category": "Store"
}
} The parse method can handle data with different geometry types. Consider the following sample data:
var data2 = [
{
x: 0.5,
y: 102.0,
prop0: 'value0'
},
{
line: [[102.0, 0.0], [103.0, 1.0], [104.0, 0.0], [105.0, 1.0]],
prop0: 'value0',
prop1: 0.0
},
{
polygon: [
[ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0] ]
],
prop0: 'value0',
prop1: {"this": "that"}
}
];For each geometry type, specify which attribute contains the geometric data
GeoJSON.parse(data2, {'Point': ['x', 'y'], 'LineString': 'line', 'Polygon': 'polygon'});
{
"type": "FeatureCollection",
"features": [
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [102,0.5]
},
"properties": {
"prop0": "value0"
}
},
{
"type": "Feature",
"geometry": {
"type": "LineString",
"coordinates": [[102, 0], [103, 1], [104, 0],[105, 1]]
},
"properties": {
"prop0": "value0",
"prop1": 0
}
},
{
"type": "Feature",
"geometry": {
"type": "Polygon",
"coordinates": [[[100, 0], [101, 0], [101, 1], [100, 1], [100, 0]]]
},
"properties": {
"prop0": "value0",
"prop1": {
"this": "that"
}
}
}
]
}You can also specify default settings if you will be parsing mutliple datasets with similiar attributes.
var data1 = [{ name: 'Location A', street: 'Market', x: 34, y: -75 }];
var data2 = [{ name: 'Location B', date: '11/23/2012', x: 54, y: -98 }];
GeoJSON.defaults = {Point: ['x', 'y'], include: ['name']};
GeoJSON.parse(data1, {});
{
"type": "FeatureCollection",
"features": [
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [-75, 34]
},
"properties": {
"name": "Location A"
}
}
]
}
GeoJSON.parse(data2, {});
{
"type": "FeatureCollection",
"features": [
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [-98, 54]
},
"properties": {
"name": "Location B"
}
}
]
}You can specify a callback function as an option third parameter.
GeoJSON.parse(data, {Point: ['lat', 'lng']}, function(geojson){
console.log(JSON.stringify(geojson));
});Depending on which makes more sense for the data that is being parsed, either specify an array of attributes to include or exclude in properties for each feature. If neither include nor exclude is set, all the attributes (besides the attributes containing the geometry data) will be added to feature properties.
include- Array of attributes to include inpropertiesfor each feature. All other fields will be ignored.exclude- Array of attributes that shouldn't be included in featureproperties. All other attributes will be added (besides geometry attributes)
The geometry parameters specify which attribute(s) contain(s) the geographic/geometric data. A geometry parameter must be specified for each type of geometry object that is present in the data that is being parsed. For example, if the data contains both points and polygons, specify both the Point and Polygon parameters. Note that geometry parameters must be in proper case. See the GeoJSON spec for details on each geometry type. The structure of the geometry parameter is:
ParameterName: 'attributeName'
Except for Point, which can be specified with a field name or an array of field names, i.e:
data = [{ name: 'location', x: 34, y: 85 }];
GeoJSON.parse(data, {Point: ['lat', 'lng']});
or
data = [{ name: 'location', coords: [85, 34] }];
GeoJSON.parse(data, {Point: 'coords'});
The valid geometry types are
PointMultiPointLineStringMultiLineStringPolygonMultiPolygon
To parse already encoded GeoJSON use
GeoJSON
var data = [{name: 'Location A', geo: {"type": "Point", "coordinates": [125.6, 10.1]}}];
GeoJSON.parse(data, {GeoJSON: 'geo'});
"type": "FeatureCollection",
"features": [{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [125.6, 10.1]
},
"properties": {
"name": "Location A"
}
}]
}
geojson.js also supports the optional GeoJSON properties bbox and crs.
crs- An object identifying a coordinate reference system. More informationbbox- A bounding box for the feature collection. An array with the following format:[y1, x1, y2, x2]. More information
You can add arbitrary properties to features using the extra param. The value for extra must be an object. For example, using the original sample data:
GeoJSON.parse(data, {
Point: ['lat', 'lng'],
extra: {
style: {
"color": "#ff7800",
"weight": 5,
"opacity": 0.65
}
}
});
{
"type": "FeatureCollection",
"features": [
{ "type": "Feature",
"geometry": {"type": "Point", "coordinates": [-75.343, 39.984]},
"properties": {
"name": "Location A",
"category": "Store",
"style": {
"color": "#ff7800",
"weight": 5,
"opacity": 0.65
}
}
},
...
}
You can also add dataset properties using the extraGlobal param. The value for extraGlobal must be an object.
GeoJSON.parse(data, {
Point: ['lat', 'lng'],
extraGlobal: {
'Creator': 'Mr. Example',
'records': data.length,
'summary': 'A few example points'
}
});
{
"type": "FeatureCollection",
"features": [
{ "type": "Feature",
"geometry": {"type": "Point", "coordinates": [-75.343, 39.984]},
"properties": {
"name": "Location A"
}
},
...
{ "type": "Feature",
"geometry": {"type": "Point", "coordinates": [ -75.534, 39.123]},
"properties": {
"name": "Location C"
}
}
],
"properties": {
"Creator": "Mr. Example",
"records": 2,
"summary": "A few example points"
}
}
For node, $ npm test.
For the browser, visit test/test.html.
$ grunt will run test.js, then lint and minify geojson.js.
$ grunt all will do all the above, plus run the browser tests, test.html. Note that this requires PhantomJS.
Licensed under the MIT License. See LICENSE for details.