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Transform.js
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139 lines (125 loc) · 4.81 KB
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import L from "leaflet";
import {CommonUtil} from '@supermap/iclient-common';
/**
* @function L.Util.transform
* @description 将要素转换为指定坐标。
* @param {(L.marker|L.circleMarker|L.polyline|L.polygon|L.rectangle|L.latLngBounds|L.bounds|Object)} feature - 待转要素包括 Leaflet Vector Layers
* 的 L.marker|L.circleMarker|L.polyline|L.polygon|L.rectangle|L.latLngBounds|L.bounds 类型和 GeoJOSN 规范数据类型
* @param {L.Proj.CRS} [sourceCRS=L.CRS.EPSG4326] - 要素转换目标坐标系，默认为 L.CRS.EPSG4326
* @param {L.Proj.CRS} targetCRS - 要素转换目标坐标系
* @return {Object} 返回GeoJOSN 规范数据类型
*/
export var transform = function (feature, sourceCRS = L.CRS.EPSG4326, targetCRS) {
let selfFeatures = null;
let selfCallback = null;
//将数据统一为 geojson 格式处理：
if (["FeatureCollection", "Feature", "Geometry"].indexOf(feature.type) === -1) {
if (feature.toGeoJSON) {
feature = feature.toGeoJSON();
} else if (feature instanceof L.LatLngBounds) {
feature = L.rectangle(feature).toGeoJSON();
} else if (feature instanceof L.Bounds) {
feature = L.rectangle([[feature.getTopLeft().x, feature.getTopLeft().y],
[feature.getBottomRight().x, feature.getBottomRight().y]]).toGeoJSON();
} else {
throw new Error("This tool only supports data conversion in geojson format or Vector Layers of Leaflet.")
}
}
//geojson 几种数据类型及处理形式
const parseCoords = {
"point": function (array) {
return selfCallback(array);
},
"multipoint": function (array) {
return parseCoords["linestring"].apply(this, [array])
},
"linestring": function (array) {
let points = [];
let p = null;
for (let i = 0, len = array.length; i < len; ++i) {
try {
p = parseCoords["point"].apply(this, [array[i]]);
} catch (err) {
throw err;
}
points.push(p);
}
return points;
},
"multilinestring": function (array) {
return parseCoords["polygon"].apply(this, [array]);
},
"polygon": function (array) {
let rings = [];
let l;
for (let i = 0, len = array.length; i < len; ++i) {
try {
l = parseCoords["linestring"].apply(this, [array[i]]);
} catch (err) {
throw err;
}
rings.push(l);
}
return rings;
},
"multipolygon": function (array) {
let polys = [];
let p = null;
for (let i = 0, len = array.length; i < len; ++i) {
try {
p = parseCoords["polygon"].apply(this, [array[i]]);
} catch (err) {
throw err;
}
polys.push(p);
}
return polys;
}
};
//返回结果：
return featureTransform(feature, _transformCoordinates);
function featureTransform(feature, callback) {
selfFeatures = feature;
selfCallback = callback;
//分离处理：
if (feature.type === "Feature") {
selfFeatures = _prepareFeatuers(feature);
} else if (feature.type === "FeatureCollection") {
let featureResults = [];
for (let i = 0; i < feature.features.length; ++i) {
try {
featureResults.push(_prepareFeatuers(feature.features[i]));
} catch (err) {
featureResults = null;
}
}
selfFeatures.features = featureResults;
}
return selfFeatures;
}
function _prepareFeatuers(feature) {
const geometry = feature.geometry;
if (!(CommonUtil.isArray(geometry.coordinates))) {
throw "Geometry must have coordinates array: " + geometry;
}
if (!parseCoords[geometry.type.toLowerCase()]) {
throw "Unsupported geometry type: " + geometry.type;
}
try {
geometry.coordinates = parseCoords[geometry.type.toLowerCase()].apply(
this, [geometry.coordinates]
);
} catch (err) {
throw err;
}
feature.geometry = geometry;
return feature;
}
function _transformCoordinates(coordinates) {
//判断code 是投影坐标还是地理坐标
var point = sourceCRS.unproject({x: coordinates[0], y: coordinates[1]});
const transform = targetCRS.project(point);
return [transform.x, transform.y];
}
};
L.Util.transform = transform;