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