MapTools

A set of GeoJSON tools

Read GeoJSON Specification

Getting Started

1. Install the library:

   npm install @barcia/maptools

2. Import some utility in your JS code

   import { Feature } from 'maptools'

3. Create a new GeoJSON feature

   const feature = new Feature('Point', [103.32, 34.21], { name: "Interesting point" })
   
   const geojsonFeature = feature.toJSON()

API

Table of Contents

• Feature
  • Parameters
  • Examples
  • addProperty
    • Parameters
    • Examples
  • toJSON
    • Examples
  • fromJSON
    • Parameters
    • Examples
• FeatureCollection
  • Parameters
  • Examples
  • addFeatures
    • Parameters
    • Examples
  • removeFeatures
    • Parameters
    • Examples
  • toJSON
    • Examples
  • fromJSON
    • Parameters
    • Examples
• Geometry
  • Parameters
  • Examples
  • toJSON
    • Examples
  • fromJSON
    • Parameters
    • Examples
  • validate
    • Parameters
    • Examples
• GeometryCollection
  • Parameters
  • Examples
  • addGeometries
    • Parameters
    • Examples
  • toJSON
    • Examples
  • fromJSON
    • Parameters
    • Examples

Feature

Create a GeoJSON Feature.

Parameters

• type ("Point" | "LineString" | "Polygon" | "MultiPoint" | "MultiLineString" | "MultiPolygon") The Feature type.
• coords Array The Feature coordinates with the format [lon, lat, alt], while alt is optional.
• props Object? The Feature properties.

Examples

const feature = new Feature('Point', [105.0, 4.0], { name: 'foo' });

addProperty

Add a new property to the Feature or update an existing one.

Parameters

• key string The property key.
• value any The property value.

Examples

feature.addProperty('desc', 'bar');

toJSON

Return the Feature object.

Examples

feature.toJSON();

Returns Object The Feature object

fromJSON

Create a Feature instance from a GeoJSON feature object.

Parameters

• json Object A valid GeoJSON feature object.

  • json.type ("Feature") The feature type.

  • json.geometry Object A valid GeoJSON geometry.

    • json.geometry.type ("Point" | "LineString" | "Polygon" | "MultiPoint" | "MultiLineString" | "MultiPolygon") The Feature geometry type.
    • json.geometry.coordinates Array The Feature coordinates with the format [lon, lat, alt], while alt is optional.

  • json.properties Object? The Feature properties.

Examples

const feature = Feature.fromJSON({
	type: 'Feature',
	geometry: {
		type: 'Point',
		coordinates: [105.0, 4.0]
	},
	properties: {
		name: 'foo'
	}
});

Returns Feature The Feature instance.

FeatureCollection

Create a FeatureCollection.

Parameters

• features Array The FeatureCollection features array.
• props Object? The FeatureCollection properties.

Examples

const featureCollection = new FeatureCollection([
	new Feature('Point', [100.0, 0.0]).toJSON(),
	new Feature('Point', [101.0, 1.0]).toJSON()
], { name: 'foo' });

addFeatures

Add new features to the FeatureCollection.

Parameters

• features Array The array with Features to add.

Examples

featureCollection.addFeatures([
	new Feature('Point', [103.0, 7.0]).toJSON(),
]);

removeFeatures

Remove features from the FeatureCollection.

Parameters

• func Function The function to filter the features to remove. Uses native JS Array.filter() method.
• dryrun boolean IF true, return the features to remove but don't remove them. (optional, default false)

Examples

featureCollection.removeFeatures(feature => feature.properties.name === 'foo');

toJSON

Return the FeatureCollection object.

Examples

featureCollection.toJSON();

Returns Object The FeatureCollection object

fromJSON

Create a FeatureCollection instance from a GeoJSON featureCollection object.

Parameters

• json Object A valid GeoJSON featureCollection object.

  • json.type ("FeatureCollection") The featureCollection type.
  • json.features Array An array of features.
  • json.properties Object? The FeatureCollection properties.

Examples

const featureCollection = FeatureCollection.fromJSON({
	type: 'FeatureCollection',
	features: [
		{
			type: 'Feature',
			geometry: {
				type: 'Point',
				coordinates: [100.0, 0.0]
			},
		},
	]
});

Returns FeatureCollection The FeatureCollection instance.

Geometry

Create a GeoJSON Geometry.

Parameters

• type ("Point" | "LineString" | "Polygon" | "MultiPoint" | "MultiLineString" | "MultiPolygon") The Geometry type.
• coords Array The Geometry coordinates with the format [lon, lat, alt], while alt is optional.

Examples

const geometry = new Geometry('Point', [105.0, 4.0]);

toJSON

Return the Geometry object.

Examples

// { type: 'Point', coordinates: [105.0, 4.0] }
geometry.toJSON();

Returns Object The Geometry object

fromJSON

Create a Geometry instance from a GeoJSON geometry object.

Parameters

• json Object A valid GeoJSON geometry object.

  • json.type ("Point" | "LineString" | "Polygon" | "MultiPoint" | "MultiLineString" | "MultiPolygon") The Geometry type.
  • json.coordinates Array The Geometry coordinates with the format [lon, lat, alt], while alt is optional.

Examples

const geometry = Geometry.fromJSON({
		type: 'Point',
		coordinates: [105.0, 4.0]
	});

Returns Geometry The Geometry instance.

validate

Validate a Geometry.

Parameters

• type ("Point" | "LineString" | "Polygon" | "MultiPoint" | "MultiLineString" | "MultiPolygon") The Geometry type.
• coords Array The Geometry coordinates with the format [lon, lat, alt], while alt is optional.

Examples

const isValidPoint = Geometry.validate({
		type: 'Point',
		coordinates: [105.0, 4.0]
	});

Returns boolean True if the Geometry is valid, false otherwise.

GeometryCollection

Create a GeometryCollection.

Parameters

• geometries Array The GeometryCollection features array.

Examples

const geometryCollection = new GeometryCollection([
	new Geometry('Point', [100.0, 0.0]).toJSON(),
	new Geometry('Point', [101.0, 1.0]).toJSON()
]);

addGeometries

Add new geometries to the GeometryCollection.

Parameters

• geometries Array The array with geometries to add.

Examples

geometryCollection.addGeometries([
	new Geometry('Point', [103.0, 7.0]).toJSON(),
]);

toJSON

Return the GeometryCollection object.

Examples

geometryCollection.toJSON();

Returns Object The GeometryCollection object

fromJSON

Create a GeometryCollection from a GeoJSON geometryCollection object.

Parameters

• json Object A valid GeoJSON geometryCollection object.

  • json.type ("GeometryCollection") The geometryCollection type.
  • json.geometries Array An array of geometries.

Examples

const geometryCollection = GeometryCollection.fromJSON({
	type: 'GeometryCollection',
	geometries: [
		{
			type: 'Point',
			coordinates: [100.0, 0.0]
		},
		{
			type: 'Point',
			coordinates: [101.0, 1.0]
		}
	]
});

Returns GeometryCollection The GeometryCollection instance.