Method _handleMultyPolygon

src/common/mapping/WebMapV2.js:3194–3220

* @private * @function WebMapV2.prototype._handleMultyPolygon * @description 处理复杂面情况

(features)

     * @description 处理复杂面情况
     */
    _handleMultyPolygon(features) {
      features.forEach((feature) => {
        if (feature.geometry.type !== 'Polygon') {
          return;
        }
        let coords = feature.geometry.coordinates;
        if (coords.length > 1) {
          let coordinates = [[coords[0]]];
          for (let index = 1; index < coords.length; index++) {
            const element = coords[index];
            const area = this.signedArea(element);
            if (area === 0) {
              continue;
            }
            if (area > 0) {
              coordinates[coordinates.length - 1].push(coords[index]);
            } else {
              coordinates.push([coords[index]]);
            }
          }

          feature.geometry.coordinates = coordinates;
          feature.geometry.type = 'MultiPolygon';
        }
      });
      return features;
    }

    signedArea(ring) {
      let sum = 0;