Add geojson module in io package

src/ol/io/geojson.js

@@ -0,0 +1,145 @@
+goog.provide('ol.io.geojson');
+
+goog.require('ol.geom.Geometry');
+goog.require('ol.geom.LineString');
+goog.require('ol.geom.MultiLineString');
+goog.require('ol.geom.MultiPoint');
+goog.require('ol.geom.MultiPolygon');
+goog.require('ol.geom.Point');
+goog.require('ol.geom.Polygon');
+
+
+/**
+ * Parse a GeoJSON string.
+ * @param {string} str GeoJSON string.
+ * @return {ol.geom.Geometry|Array.<ol.geom.Geometry>} Parsed geometry or array
+ *    of geometries.
+ */
+ol.io.geojson.read = function(str) {
+  // TODO: add options and accept projection
+  var json = /** @type {GeoJSONObject} */ (JSON.parse(str));
+  return ol.io.geojson.parse_(json);
+};
+
+
+/**
+ * @param {GeoJSONObject} json GeoJSON object.
+ * @return {ol.geom.Geometry|Array.<ol.geom.Geometry>} Parsed geometry or array
+ *    of geometries.
+ * @private
+ */
+ol.io.geojson.parse_ = function(json) {
+  var result;
+  switch (json.type) {
+    case 'GeometryCollection':
+      result = ol.io.geojson.parseGeometryCollection_(
+          /** @type {GeoJSONGeometryCollection} */ (json));
+      break;
+    case 'Point':
+      result = ol.io.geojson.parsePoint_(
+          /** @type {GeoJSONGeometry} */ (json));
+      break;
+    case 'LineString':
+      result = ol.io.geojson.parseLineString_(
+          /** @type {GeoJSONGeometry} */ (json));
+      break;
+    case 'Polygon':
+      result = ol.io.geojson.parsePolygon_(
+          /** @type {GeoJSONGeometry} */ (json));
+      break;
+    case 'MultiPoint':
+      result = ol.io.geojson.parseMultiPoint_(
+          /** @type {GeoJSONGeometry} */ (json));
+      break;
+    case 'MultiLineString':
+      result = ol.io.geojson.parseMultiLineString_(
+          /** @type {GeoJSONGeometry} */ (json));
+      break;
+    case 'MultiPolygon':
+      result = ol.io.geojson.parseMultiPolygon_(
+          /** @type {GeoJSONGeometry} */ (json));
+      break;
+    default:
+      throw new Error('GeoJSON parsing not implemented for type: ' + json.type);
+  }
+  return result;
+};
+
+
+/**
+ * @param {GeoJSONGeometryCollection} json GeoJSON geometry collection.
+ * @return {Array.<ol.geom.Geometry>} Parsed array of geometries.
+ * @private
+ */
+ol.io.geojson.parseGeometryCollection_ = function(json) {
+  var geometries = json.geometries,
+      len = geometries.length,
+      result = new Array(len),
+      i;
+
+  for (i = 0; i < len; ++i) {
+    result[i] = ol.io.geojson.parse_(
+        /** @type {GeoJSONGeometry} */ (geometries[i]));
+  }
+  return result;
+};
+
+
+/**
+ * @param {GeoJSONGeometry} json GeoJSON linestring.
+ * @return {ol.geom.LineString} Parsed linestring.
+ * @private
+ */
+ol.io.geojson.parseLineString_ = function(json) {
+  return new ol.geom.LineString(json.coordinates);
+};
+
+
+/**
+ * @param {GeoJSONGeometry} json GeoJSON multi-linestring.
+ * @return {ol.geom.MultiLineString} Parsed multi-linestring.
+ * @private
+ */
+ol.io.geojson.parseMultiLineString_ = function(json) {
+  return new ol.geom.MultiLineString(json.coordinates);
+};
+
+
+/**
+ * @param {GeoJSONGeometry} json GeoJSON multi-point.
+ * @return {ol.geom.MultiPoint} Parsed multi-point.
+ * @private
+ */
+ol.io.geojson.parseMultiPoint_ = function(json) {
+  return new ol.geom.MultiPoint(json.coordinates);
+};
+
+
+/**
+ * @param {GeoJSONGeometry} json GeoJSON multi-polygon.
+ * @return {ol.geom.MultiPolygon} Parsed multi-polygon.
+ * @private
+ */
+ol.io.geojson.parseMultiPolygon_ = function(json) {
+  return new ol.geom.MultiPolygon(json.coordinates);
+};
+
+
+/**
+ * @param {GeoJSONGeometry} json GeoJSON point.
+ * @return {ol.geom.Point} Parsed multi-point.
+ * @private
+ */
+ol.io.geojson.parsePoint_ = function(json) {
+  return new ol.geom.Point(json.coordinates);
+};
+
+
+/**
+ * @param {GeoJSONGeometry} json GeoJSON polygon.
+ * @return {ol.geom.Polygon} Parsed polygon.
+ * @private
+ */
+ol.io.geojson.parsePolygon_ = function(json) {
+  return new ol.geom.Polygon(json.coordinates);
+};