datavizstocklib/src/geoutil.js

测试一下呗

/** 地图解压缩工具类  */
export class GeoUtil {
    constructor() { }

    /**解压入口 传入压缩后的json */
    decode(json) {
        if (!json.UTF8Encoding) {
            return json;
        }
        var encodeScale = json.UTF8Scale;
        if (encodeScale == null) {
            encodeScale = 1024;
        }

        var features = json.features;

        for (var f = 0; f < features.length; f++) {
            var feature = features[f];
            var geometry = feature.geometry;
            var coordinates = geometry.coordinates;
            var encodeOffsets = geometry.encodeOffsets;

            for (var c = 0; c < coordinates.length; c++) {
                var coordinate = coordinates[c];

                if (geometry.type === 'Polygon') {
                    coordinates[c] = this.decodePolygon(
                        coordinate,
                        encodeOffsets[c],
                        encodeScale
                    );
                } else if (geometry.type === 'MultiPolygon') {
                    for (var c2 = 0; c2 < coordinate.length; c2++) {
                        var polygon = coordinate[c2];
                        coordinate[c2] = this.decodePolygon(
                            polygon,
                            encodeOffsets[c][c2],
                            encodeScale
                        );
                    }
                }
            }
        }
        // Has been decoded
        json.UTF8Encoding = false;
        return json;
    }

    decodePolygon(coordinate, encodeOffsets, encodeScale) {
        var result = [];
        var prevX = encodeOffsets[0];
        var prevY = encodeOffsets[1];

        for (var i = 0; i < coordinate.length; i += 2) {
            var x = coordinate.charCodeAt(i) - 64;
            var y = coordinate.charCodeAt(i + 1) - 64;
            // ZigZag decoding
            x = (x >> 1) ^ (-(x & 1));
            y = (y >> 1) ^ (-(y & 1));
            // Delta deocding
            x += prevX;
            y += prevY;

            prevX = x;
            prevY = y;
            result.push([x / encodeScale, y / encodeScale]);
        }
        return result;
    }
}
export default GeoUtil;