Add ol.reader.GeoJSON

src/ol/reader/geojson/geojson.js

@@ -0,0 +1,139 @@
+// FIXME coordinate order
+// FIXME reprojection
+// FIXME support other geometry types
+
+goog.provide('ol.reader.GeoJSON');
+
+goog.require('goog.asserts');
+goog.require('goog.json');
+goog.require('ol.Feature');
+goog.require('ol.geom.LineString');
+goog.require('ol.geom.Point');
+goog.require('ol.geom.Polygon');
+
+
+
+/**
+ * @constructor
+ */
+ol.reader.GeoJSON = function() {
+};
+
+
+/**
+ * @param {GeoJSONGeometry} geometry Geometry.
+ * @private
+ * @return {ol.geom.Point} Point.
+ */
+ol.reader.GeoJSON.readPointGeometry_ = function(geometry) {
+  goog.asserts.assert(geometry.type == 'Point');
+  return new ol.geom.Point(geometry.coordinates);
+};
+
+
+/**
+ * @param {GeoJSONGeometry} geometry Geometry.
+ * @private
+ * @return {ol.geom.LineString} LineString.
+ */
+ol.reader.GeoJSON.readLineStringGeometry_ = function(geometry) {
+  goog.asserts.assert(geometry.type == 'LineString');
+  return new ol.geom.LineString(geometry.coordinates);
+};
+
+
+/**
+ * @param {GeoJSONGeometry} geometry Geometry.
+ * @private
+ * @return {ol.geom.Polygon} Polygon.
+ */
+ol.reader.GeoJSON.readPolygonGeometry_ = function(geometry) {
+  goog.asserts.assert(geometry.type == 'Polygon');
+  return new ol.geom.Polygon(geometry.coordinates);
+};
+
+
+/**
+ * @param {GeoJSONFeature} feature Feature.
+ * @param {function(ol.Feature): *} callback Callback.
+ * @private
+ * @return {*} Callback result.
+ */
+ol.reader.GeoJSON.readFeature_ = function(feature, callback) {
+  goog.asserts.assert(feature.type == 'Feature');
+  var geometryReader =
+      ol.reader.GeoJSON.GEOMETRY_READERS_[feature.geometry.type];
+  goog.asserts.assert(goog.isDef(geometryReader));
+  var geometry = geometryReader(feature.geometry);
+  var f = new ol.Feature(geometry);
+  if (goog.isDef(feature.properties)) {
+    f.setValues(feature.properties);
+  }
+  return callback(f);
+};
+
+
+/**
+ * @param {GeoJSONFeatureCollection} featureCollection Feature collection.
+ * @param {function(ol.Feature): *} callback Callback.
+ * @private
+ * @return {*} Callback result.
+ */
+ol.reader.GeoJSON.readFeatureCollection_ =
+    function(featureCollection, callback) {
+  goog.asserts.assert(featureCollection.type == 'FeatureCollection');
+  var features = featureCollection.features;
+  var i, ii;
+  for (i = 0, ii = features.length; i < ii; ++i) {
+    var result = ol.reader.GeoJSON.readFeature_(features[i], callback);
+    if (result) {
+      return result;
+    }
+  }
+  return undefined;
+};
+
+
+/**
+ * @param {GeoJSONObject} object Object.
+ * @param {function(ol.Feature): *} callback Callback.
+ * @return {*} Callback result.
+ */
+ol.reader.GeoJSON.readObject = function(object, callback) {
+  var objectReader = ol.reader.GeoJSON.OBJECT_READERS_[object.type];
+  goog.asserts.assert(goog.isDef(objectReader));
+  return objectReader(object, callback);
+};
+
+
+/**
+ * @param {string} string String.
+ * @param {function(ol.Feature): *} callback Callback.
+ * @return {*} Callback result.
+ */
+ol.reader.GeoJSON.readString = function(string, callback) {
+  var object = goog.json.parse(string);
+  return ol.reader.GeoJSON.readObject(
+      /** @type {GeoJSONObject} */ (object), callback);
+};
+
+
+/**
+ * @private
+ * @type {Object.<string, function(GeoJSONGeometry): ol.geom.Geometry>}
+ */
+ol.reader.GeoJSON.GEOMETRY_READERS_ = {
+  'Point': ol.reader.GeoJSON.readPointGeometry_,
+  'LineString': ol.reader.GeoJSON.readLineStringGeometry_,
+  'Polygon': ol.reader.GeoJSON.readPolygonGeometry_
+};
+
+
+/**
+ * @private
+ * @type {Object.<string, function(*, function(ol.Feature): *): *>}
+ */
+ol.reader.GeoJSON.OBJECT_READERS_ = {
+  'Feature': ol.reader.GeoJSON.readFeature_,
+  'FeatureCollection': ol.reader.GeoJSON.readFeatureCollection_
+};

test/spec/ol/reader/geojson.test.js

@@ -0,0 +1,111 @@
+goog.provide('ol.test.reader.GeoJSON');
+
+
+describe('ol.reader.GeoJSON', function() {
+
+  var pointGeoJSON = {
+    'type': 'Feature',
+    'geometry': {
+      'type': 'Point',
+      'coordinates': [102.0, 0.5]
+    },
+    'properties': {
+      'prop0': 'value0'
+    }
+  };
+
+  var lineStringGeoJSON = {
+    'type': 'Feature',
+    'geometry': {
+      'type': 'LineString',
+      'coordinates': [
+        [102.0, 0.0], [103.0, 1.0], [104.0, 0.0], [105.0, 1.0]
+      ]
+    },
+    'properties': {
+      'prop0': 'value0',
+      'prop1': 0.0
+    }
+  };
+
+  var polygonGeoJSON = {
+    'type': 'Feature',
+    'geometry': {
+      'type': 'Polygon',
+      'coordinates': [[
+        [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0]
+      ]]
+    },
+    'properties': {
+      'prop0': 'value0',
+      'prop1': {'this': 'that'}
+    }
+  };
+
+  var featureCollectionGeoJSON = {
+    'type': 'FeatureCollection',
+    'features': [pointGeoJSON, lineStringGeoJSON, polygonGeoJSON]
+  };
+
+  describe('readObject', function() {
+
+    it('can read a single point feature', function() {
+      var feature = ol.reader.GeoJSON.readObject(pointGeoJSON, function(f) {
+        return f;
+      });
+      expect(feature).to.be.an(ol.Feature);
+      var geometry = feature.getGeometry();
+      expect(geometry).to.be.an(ol.geom.Point);
+      expect(geometry.getCoordinate()).to.eql([102.0, 0.5]);
+      expect(feature.get('prop0')).to.be('value0');
+    });
+
+    it('can read a single line string feature', function() {
+      var feature = ol.reader.GeoJSON.readObject(lineStringGeoJSON,
+          function(f) {
+            return f;
+          });
+      expect(feature).to.be.an(ol.Feature);
+      var geometry = feature.getGeometry();
+      expect(geometry).to.be.an(ol.geom.LineString);
+      expect(geometry.getCoordinates()).to.eql(
+          [[102.0, 0.0], [103.0, 1.0], [104.0, 0.0], [105.0, 1.0]]);
+      expect(feature.get('prop0')).to.be('value0');
+      expect(feature.get('prop1')).to.be(0.0);
+    });
+
+    it('can read a single polygon feature', function() {
+      var feature = ol.reader.GeoJSON.readObject(polygonGeoJSON, function(f) {
+        return f;
+      });
+      expect(feature).to.be.an(ol.Feature);
+      var geometry = feature.getGeometry();
+      expect(geometry).to.be.an(ol.geom.Polygon);
+      expect(geometry.getRings()).to.eql([[
+        [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0]
+      ]]);
+      expect(feature.get('prop0')).to.be('value0');
+      expect(feature.get('prop1')).to.eql({'this': 'that'});
+    });
+
+    it('can read a feature collection', function() {
+      var features = [];
+      ol.reader.GeoJSON.readObject(featureCollectionGeoJSON, function(f) {
+        features.push(f);
+      });
+      expect(features).to.have.length(3);
+      expect(features[0].getGeometry()).to.be.an(ol.geom.Point);
+      expect(features[1].getGeometry()).to.be.an(ol.geom.LineString);
+      expect(features[2].getGeometry()).to.be.an(ol.geom.Polygon);
+    });
+
+  });
+
+});
+
+
+goog.require('ol.Feature');
+goog.require('ol.geom.LineString');
+goog.require('ol.geom.Point');
+goog.require('ol.geom.Polygon');
+goog.require('ol.reader.GeoJSON');