Method read

src/common/format/GeoJSON.js:446–513

* @function GeoJSONFormat.prototype.read * @description 将 GeoJSON 对象或者 GeoJSON 对象字符串转换为 SuperMap Feature 对象。 * @param {GeoJSONObject} json - GeoJSON 对象。 * @param {string} [type='FeaureCollection'] - 可选的字符串，它决定了输出的格式。支持的值有："Geometry","Feature"，和 "FeatureCollection"，如果此值为null。 * @p

(json, type, filter)

     */

    read(json, type, filter) {
        type = (type) ? type : "FeatureCollection";
        var results = null;
        var obj = null;
        if (typeof json == "string") {
            obj = super.read(json, filter);
        } else {
            obj = json;
        }
        if (!obj) {
            //console.error("Bad JSON: " + json);
        } else if (typeof (obj.type) != "string") {
            //console.error("Bad GeoJSON - no type: " + json);
        } else if (this.isValidType(obj, type)) {
            switch (type) {
                case "Geometry":
                    try {
                        results = this.parseGeometry(obj);
                    } catch (err) {
                        //console.error(err);
                    }
                    break;
                case "Feature":
                    try {
                        results = this.parseFeature(obj);
                        results.type = "Feature";
                    } catch (err) {
                        //console.error(err);
                    }
                    break;
                case "FeatureCollection":
                    // for type FeatureCollection, we allow input to be any type
                    results = [];
                    switch (obj.type) {
                        case "Feature":
                            try {
                                results.push(this.parseFeature(obj));
                            } catch (err) {
                                results = null;
                                //console.error(err);
                            }
                            break;
                        case "FeatureCollection":
                            for (var i = 0, len = obj.features.length; i < len; ++i) {
                                try {
                                    results.push(this.parseFeature(obj.features[i]));
                                } catch (err) {
                                    results = null;
                                    // console.error(err);
                                }
                            }
                            break;
                        default:
                            try {
                                var geom = this.parseGeometry(obj);
                                results.push(new Vector(geom));
                            } catch (err) {
                                results = null;