114 lines
3.2 KiB
Plaintext
114 lines
3.2 KiB
Plaintext
/**
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* Parse and decode geo json
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* @module echarts/coord/geo/parseGeoJson
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*/
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define(function (require) {
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var zrUtil = require('zrender/core/util');
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var Region = require('./Region');
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function decode(json) {
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if (!json.UTF8Encoding) {
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return json;
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}
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var features = json.features;
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for (var f = 0; f < features.length; f++) {
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var feature = features[f];
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var geometry = feature.geometry;
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var coordinates = geometry.coordinates;
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var encodeOffsets = geometry.encodeOffsets;
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for (var c = 0; c < coordinates.length; c++) {
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var coordinate = coordinates[c];
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if (geometry.type === 'Polygon') {
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coordinates[c] = decodePolygon(
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coordinate,
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encodeOffsets[c]
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);
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}
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else if (geometry.type === 'MultiPolygon') {
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for (var c2 = 0; c2 < coordinate.length; c2++) {
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var polygon = coordinate[c2];
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coordinate[c2] = decodePolygon(
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polygon,
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encodeOffsets[c][c2]
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);
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}
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}
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}
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}
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// Has been decoded
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json.UTF8Encoding = false;
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return json;
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}
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function decodePolygon(coordinate, encodeOffsets) {
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var result = [];
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var prevX = encodeOffsets[0];
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var prevY = encodeOffsets[1];
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for (var i = 0; i < coordinate.length; i += 2) {
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var x = coordinate.charCodeAt(i) - 64;
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var y = coordinate.charCodeAt(i + 1) - 64;
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// ZigZag decoding
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x = (x >> 1) ^ (-(x & 1));
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y = (y >> 1) ^ (-(y & 1));
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// Delta deocding
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x += prevX;
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y += prevY;
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prevX = x;
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prevY = y;
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// Dequantize
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result.push([x / 1024, y / 1024]);
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}
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return result;
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}
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/**
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* @inner
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*/
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function flattern2D(array) {
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var ret = [];
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for (var i = 0; i < array.length; i++) {
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for (var k = 0; k < array[i].length; k++) {
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ret.push(array[i][k]);
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}
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}
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return ret;
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}
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/**
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* @alias module:echarts/coord/geo/parseGeoJson
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* @param {Object} geoJson
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* @return {module:zrender/container/Group}
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*/
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return function (geoJson) {
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decode(geoJson);
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return zrUtil.map(zrUtil.filter(geoJson.features, function (featureObj) {
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// Output of mapshaper may have geometry null
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return featureObj.geometry && featureObj.properties;
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}), function (featureObj) {
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var properties = featureObj.properties;
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var geometry = featureObj.geometry;
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var coordinates = geometry.coordinates;
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if (geometry.type === 'MultiPolygon') {
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coordinates = flattern2D(coordinates);
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}
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return new Region(
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properties.name,
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coordinates,
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properties.cp
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);
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});
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};
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}); |