113 lines
3.6 KiB
JavaScript
113 lines
3.6 KiB
JavaScript
import * as jsonData from "./geoJSONData";
|
|
|
|
const scale = 6; //默认缩放比
|
|
const coordinateSpanByZoom = { //各缩放比例下map显示范围的经纬度跨度
|
|
6: [60, 20]
|
|
};
|
|
export const worldData = jsonData["world"];
|
|
const worldDataDecode = decode(worldData);
|
|
|
|
/*export function getProvinceJson(coordinate) { //根据中心点坐标，动态返回四周的省份信息。
|
|
//同时间只显示自身和周围共9块省级区划
|
|
//console.info(coordinate);
|
|
let countryNames = getCountries(coordinate, scale);
|
|
//console.info(countryNames.join("\n"));
|
|
//拼接json
|
|
let newWorldData = JSON.parse(JSON.stringify(worldDataDecode));
|
|
countryNames.forEach(countryName => {
|
|
if (jsonData[countryName]) {
|
|
//let countryDecode = jsonData[countryName];
|
|
let countryDecode = decode(jsonData[countryName]);
|
|
//console.info(countryDecode)
|
|
newWorldData.features = newWorldData.features.concat(countryDecode.features);
|
|
}
|
|
});
|
|
//console.info(JSON.stringify(newWorldData.features[newWorldData.features.length-1]));
|
|
return newWorldData;
|
|
}*/
|
|
/*function getCountries(coordinate, currentScale) { //根据参数当前中心坐标、当前缩放比，得出需要显示省级区划的小块内的国家
|
|
let x = coordinateSpanByZoom[currentScale][0];
|
|
let y = coordinateSpanByZoom[currentScale][1];
|
|
let rangeX = [coordinate[0] < (-180+x) ? -180 : (Math.floor(coordinate[0]/x)-1)*x, (Math.floor(coordinate[0]/x)+1)*x];
|
|
let rangeY = [coordinate[1] < (-90+y) ? -90 : (Math.floor(coordinate[1]/y)-1)*y, (Math.floor(coordinate[1]/y)+1)*y];
|
|
//console.info(rangeX, rangeY);
|
|
let countries = [];
|
|
for (let country in jsonData.countryCoordinates) { //jsonData.countryCoordinates是各国首都坐标数据
|
|
let countryX = jsonData.countryCoordinates[country][currentScale][0];
|
|
let countryY = jsonData.countryCoordinates[country][currentScale][1];
|
|
if (countryX > rangeX[0] && countryX <= rangeX[1] && countryY > rangeY[0] && countryY <= rangeY[1]) { //这个国家在范围内
|
|
//console.info(countryX, countryY);
|
|
countries.push(country);
|
|
}
|
|
}
|
|
return countries;
|
|
}*/
|
|
|
|
function 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] = decodePolygon(
|
|
coordinate,
|
|
encodeOffsets[c],
|
|
encodeScale
|
|
);
|
|
}
|
|
else if (geometry.type === 'MultiPolygon') {
|
|
for (var c2 = 0; c2 < coordinate.length; c2++) {
|
|
var polygon = coordinate[c2];
|
|
coordinate[c2] = decodePolygon(
|
|
polygon,
|
|
encodeOffsets[c][c2],
|
|
encodeScale
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
// Has been decoded
|
|
json.UTF8Encoding = false;
|
|
return json;
|
|
}
|
|
|
|
function 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;
|
|
// Dequantize
|
|
result.push([x / encodeScale, y / encodeScale]);
|
|
}
|
|
|
|
return result;
|
|
}
|