Files
openlayers/src/ol/format/GeoJSON.js
2018-07-17 16:43:53 +02:00

480 lines
14 KiB
JavaScript

/**
* @module ol/format/GeoJSON
*/
// TODO: serialize dataProjection as crs member when writing
// see https://github.com/openlayers/openlayers/issues/2078
import {assert} from '../asserts.js';
import Feature from '../Feature.js';
import {transformWithOptions} from '../format/Feature.js';
import JSONFeature from '../format/JSONFeature.js';
import GeometryCollection from '../geom/GeometryCollection.js';
import LineString from '../geom/LineString.js';
import MultiLineString from '../geom/MultiLineString.js';
import MultiPoint from '../geom/MultiPoint.js';
import MultiPolygon from '../geom/MultiPolygon.js';
import Point from '../geom/Point.js';
import Polygon from '../geom/Polygon.js';
import {assign, isEmpty} from '../obj.js';
import {get as getProjection} from '../proj.js';
/**
* @typedef {Object} Options
* @property {module:ol/proj~ProjectionLike} [dataProjection='EPSG:4326'] Default data projection.
* @property {module:ol/proj~ProjectionLike} [featureProjection] Projection for features read or
* written by the format. Options passed to read or write methods will take precedence.
* @property {string} [geometryName] Geometry name to use when creating features.
* @property {boolean} [extractGeometryName=false] Certain GeoJSON providers include
* the geometry_name field in the feature GeoJSON. If set to `true` the GeoJSON reader
* will look for that field to set the geometry name. If both this field is set to `true`
* and a `geometryName` is provided, the `geometryName` will take precedence.
*/
/**
* @classdesc
* Feature format for reading and writing data in the GeoJSON format.
*
* @api
*/
class GeoJSON extends JSONFeature {
/**
* @param {module:ol/format/GeoJSON~Options=} opt_options Options.
*/
constructor(opt_options) {
const options = opt_options ? opt_options : {};
super();
/**
* @inheritDoc
*/
this.dataProjection = getProjection(
options.dataProjection ?
options.dataProjection : 'EPSG:4326');
if (options.featureProjection) {
this.defaultFeatureProjection = getProjection(options.featureProjection);
}
/**
* Name of the geometry attribute for features.
* @type {string|undefined}
* @private
*/
this.geometryName_ = options.geometryName;
/**
* Look for the geometry name in the feature GeoJSON
* @type {boolean|undefined}
* @private
*/
this.extractGeometryName_ = options.extractGeometryName;
}
/**
* @inheritDoc
*/
readFeatureFromObject(object, opt_options) {
/**
* @type {GeoJSONFeature}
*/
let geoJSONFeature = null;
if (object.type === 'Feature') {
geoJSONFeature = /** @type {GeoJSONFeature} */ (object);
} else {
geoJSONFeature = /** @type {GeoJSONFeature} */ ({
type: 'Feature',
geometry: /** @type {GeoJSONGeometry|GeoJSONGeometryCollection} */ (object)
});
}
const geometry = readGeometry(geoJSONFeature.geometry, opt_options);
const feature = new Feature();
if (this.geometryName_) {
feature.setGeometryName(this.geometryName_);
} else if (this.extractGeometryName_ && geoJSONFeature.geometry_name !== undefined) {
feature.setGeometryName(geoJSONFeature.geometry_name);
}
feature.setGeometry(geometry);
if (geoJSONFeature.id !== undefined) {
feature.setId(geoJSONFeature.id);
}
if (geoJSONFeature.properties) {
feature.setProperties(geoJSONFeature.properties);
}
return feature;
}
/**
* @inheritDoc
*/
readFeaturesFromObject(object, opt_options) {
const geoJSONObject = /** @type {GeoJSONObject} */ (object);
/** @type {Array.<module:ol/Feature>} */
let features = null;
if (geoJSONObject.type === 'FeatureCollection') {
const geoJSONFeatureCollection = /** @type {GeoJSONFeatureCollection} */ (object);
features = [];
const geoJSONFeatures = geoJSONFeatureCollection.features;
for (let i = 0, ii = geoJSONFeatures.length; i < ii; ++i) {
features.push(this.readFeatureFromObject(geoJSONFeatures[i], opt_options));
}
} else {
features = [this.readFeatureFromObject(object, opt_options)];
}
return features;
}
/**
* @inheritDoc
*/
readGeometryFromObject(object, opt_options) {
return readGeometry(/** @type {GeoJSONGeometry} */ (object), opt_options);
}
/**
* @inheritDoc
*/
readProjectionFromObject(object) {
const geoJSONObject = /** @type {GeoJSONObject} */ (object);
const crs = geoJSONObject.crs;
let projection;
if (crs) {
if (crs.type == 'name') {
projection = getProjection(crs.properties.name);
} else {
assert(false, 36); // Unknown SRS type
}
} else {
projection = this.dataProjection;
}
return (
/** @type {module:ol/proj/Projection} */ (projection)
);
}
/**
* Encode a feature as a GeoJSON Feature object.
*
* @param {module:ol/Feature} feature Feature.
* @param {module:ol/format/Feature~WriteOptions=} opt_options Write options.
* @return {GeoJSONFeature} Object.
* @override
* @api
*/
writeFeatureObject(feature, opt_options) {
opt_options = this.adaptOptions(opt_options);
const object = /** @type {GeoJSONFeature} */ ({
'type': 'Feature'
});
const id = feature.getId();
if (id !== undefined) {
object.id = id;
}
const geometry = feature.getGeometry();
if (geometry) {
object.geometry = writeGeometry(geometry, opt_options);
} else {
object.geometry = null;
}
const properties = feature.getProperties();
delete properties[feature.getGeometryName()];
if (!isEmpty(properties)) {
object.properties = properties;
} else {
object.properties = null;
}
return object;
}
/**
* Encode an array of features as a GeoJSON object.
*
* @param {Array.<module:ol/Feature>} features Features.
* @param {module:ol/format/Feature~WriteOptions=} opt_options Write options.
* @return {GeoJSONFeatureCollection} GeoJSON Object.
* @override
* @api
*/
writeFeaturesObject(features, opt_options) {
opt_options = this.adaptOptions(opt_options);
const objects = [];
for (let i = 0, ii = features.length; i < ii; ++i) {
objects.push(this.writeFeatureObject(features[i], opt_options));
}
return /** @type {GeoJSONFeatureCollection} */ ({
type: 'FeatureCollection',
features: objects
});
}
/**
* Encode a geometry as a GeoJSON object.
*
* @param {module:ol/geom/Geometry} geometry Geometry.
* @param {module:ol/format/Feature~WriteOptions=} opt_options Write options.
* @return {GeoJSONGeometry|GeoJSONGeometryCollection} Object.
* @override
* @api
*/
writeGeometryObject(geometry, opt_options) {
return writeGeometry(geometry, this.adaptOptions(opt_options));
}
}
/**
* @const
* @type {Object.<string, function(GeoJSONObject): module:ol/geom/Geometry>}
*/
const GEOMETRY_READERS = {
'Point': readPointGeometry,
'LineString': readLineStringGeometry,
'Polygon': readPolygonGeometry,
'MultiPoint': readMultiPointGeometry,
'MultiLineString': readMultiLineStringGeometry,
'MultiPolygon': readMultiPolygonGeometry,
'GeometryCollection': readGeometryCollectionGeometry
};
/**
* @const
* @type {Object.<string, function(module:ol/geom/Geometry, module:ol/format/Feature~WriteOptions=): (GeoJSONGeometry|GeoJSONGeometryCollection)>}
*/
const GEOMETRY_WRITERS = {
'Point': writePointGeometry,
'LineString': writeLineStringGeometry,
'Polygon': writePolygonGeometry,
'MultiPoint': writeMultiPointGeometry,
'MultiLineString': writeMultiLineStringGeometry,
'MultiPolygon': writeMultiPolygonGeometry,
'GeometryCollection': writeGeometryCollectionGeometry,
'Circle': writeEmptyGeometryCollectionGeometry
};
/**
* @param {GeoJSONGeometry|GeoJSONGeometryCollection} object Object.
* @param {module:ol/format/Feature~ReadOptions=} opt_options Read options.
* @return {module:ol/geom/Geometry} Geometry.
*/
function readGeometry(object, opt_options) {
if (!object) {
return null;
}
const geometryReader = GEOMETRY_READERS[object.type];
return (
/** @type {module:ol/geom/Geometry} */ (transformWithOptions(geometryReader(object), false, opt_options))
);
}
/**
* @param {GeoJSONGeometryCollection} object Object.
* @param {module:ol/format/Feature~ReadOptions=} opt_options Read options.
* @return {module:ol/geom/GeometryCollection} Geometry collection.
*/
function readGeometryCollectionGeometry(object, opt_options) {
const geometries = object.geometries.map(
/**
* @param {GeoJSONGeometry} geometry Geometry.
* @return {module:ol/geom/Geometry} geometry Geometry.
*/
function(geometry) {
return readGeometry(geometry, opt_options);
});
return new GeometryCollection(geometries);
}
/**
* @param {GeoJSONGeometry} object Object.
* @return {module:ol/geom/Point} Point.
*/
function readPointGeometry(object) {
return new Point(object.coordinates);
}
/**
* @param {GeoJSONGeometry} object Object.
* @return {module:ol/geom/LineString} LineString.
*/
function readLineStringGeometry(object) {
return new LineString(object.coordinates);
}
/**
* @param {GeoJSONGeometry} object Object.
* @return {module:ol/geom/MultiLineString} MultiLineString.
*/
function readMultiLineStringGeometry(object) {
return new MultiLineString(object.coordinates);
}
/**
* @param {GeoJSONGeometry} object Object.
* @return {module:ol/geom/MultiPoint} MultiPoint.
*/
function readMultiPointGeometry(object) {
return new MultiPoint(object.coordinates);
}
/**
* @param {GeoJSONGeometry} object Object.
* @return {module:ol/geom/MultiPolygon} MultiPolygon.
*/
function readMultiPolygonGeometry(object) {
return new MultiPolygon(object.coordinates);
}
/**
* @param {GeoJSONGeometry} object Object.
* @return {module:ol/geom/Polygon} Polygon.
*/
function readPolygonGeometry(object) {
return new Polygon(object.coordinates);
}
/**
* @param {module:ol/geom/Geometry} geometry Geometry.
* @param {module:ol/format/Feature~WriteOptions=} opt_options Write options.
* @return {GeoJSONGeometry|GeoJSONGeometryCollection} GeoJSON geometry.
*/
function writeGeometry(geometry, opt_options) {
const geometryWriter = GEOMETRY_WRITERS[geometry.getType()];
return geometryWriter(/** @type {module:ol/geom/Geometry} */ (
transformWithOptions(geometry, true, opt_options)), opt_options);
}
/**
* @param {module:ol/geom/Geometry} geometry Geometry.
* @return {GeoJSONGeometryCollection} Empty GeoJSON geometry collection.
*/
function writeEmptyGeometryCollectionGeometry(geometry) {
return /** @type {GeoJSONGeometryCollection} */ ({
type: 'GeometryCollection',
geometries: []
});
}
/**
* @param {module:ol/geom/GeometryCollection} geometry Geometry.
* @param {module:ol/format/Feature~WriteOptions=} opt_options Write options.
* @return {GeoJSONGeometryCollection} GeoJSON geometry collection.
*/
function writeGeometryCollectionGeometry(geometry, opt_options) {
const geometries = geometry.getGeometriesArray().map(function(geometry) {
const options = assign({}, opt_options);
delete options.featureProjection;
return writeGeometry(geometry, options);
});
return /** @type {GeoJSONGeometryCollection} */ ({
type: 'GeometryCollection',
geometries: geometries
});
}
/**
* @param {module:ol/geom/LineString} geometry Geometry.
* @param {module:ol/format/Feature~WriteOptions=} opt_options Write options.
* @return {GeoJSONGeometry} GeoJSON geometry.
*/
function writeLineStringGeometry(geometry, opt_options) {
return /** @type {GeoJSONGeometry} */ ({
type: 'LineString',
coordinates: geometry.getCoordinates()
});
}
/**
* @param {module:ol/geom/MultiLineString} geometry Geometry.
* @param {module:ol/format/Feature~WriteOptions=} opt_options Write options.
* @return {GeoJSONGeometry} GeoJSON geometry.
*/
function writeMultiLineStringGeometry(geometry, opt_options) {
return /** @type {GeoJSONGeometry} */ ({
type: 'MultiLineString',
coordinates: geometry.getCoordinates()
});
}
/**
* @param {module:ol/geom/MultiPoint} geometry Geometry.
* @param {module:ol/format/Feature~WriteOptions=} opt_options Write options.
* @return {GeoJSONGeometry} GeoJSON geometry.
*/
function writeMultiPointGeometry(geometry, opt_options) {
return /** @type {GeoJSONGeometry} */ ({
type: 'MultiPoint',
coordinates: geometry.getCoordinates()
});
}
/**
* @param {module:ol/geom/MultiPolygon} geometry Geometry.
* @param {module:ol/format/Feature~WriteOptions=} opt_options Write options.
* @return {GeoJSONGeometry} GeoJSON geometry.
*/
function writeMultiPolygonGeometry(geometry, opt_options) {
let right;
if (opt_options) {
right = opt_options.rightHanded;
}
return /** @type {GeoJSONGeometry} */ ({
type: 'MultiPolygon',
coordinates: geometry.getCoordinates(right)
});
}
/**
* @param {module:ol/geom/Point} geometry Geometry.
* @param {module:ol/format/Feature~WriteOptions=} opt_options Write options.
* @return {GeoJSONGeometry} GeoJSON geometry.
*/
function writePointGeometry(geometry, opt_options) {
return /** @type {GeoJSONGeometry} */ ({
type: 'Point',
coordinates: geometry.getCoordinates()
});
}
/**
* @param {module:ol/geom/Polygon} geometry Geometry.
* @param {module:ol/format/Feature~WriteOptions=} opt_options Write options.
* @return {GeoJSONGeometry} GeoJSON geometry.
*/
function writePolygonGeometry(geometry, opt_options) {
let right;
if (opt_options) {
right = opt_options.rightHanded;
}
return /** @type {GeoJSONGeometry} */ ({
type: 'Polygon',
coordinates: geometry.getCoordinates(right)
});
}
export default GeoJSON;