天地图绘制区域图层

背景：

业务方要求将

变更点：

1.将原有的高德地图改为天地图

2.呈现形式修改：加两层遮罩：半透明遮罩层mask+区域覆盖物mask

实现过程：

1.更换地图引入源

 <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/maptalks/dist/maptalks.css" /><script type="text/javascript" src="https://cdn.jsdelivr.net/npm/maptalks/dist/maptalks.min.js"></script>

2.天地图基本配置-tk

3.实用方法封装

1）初始化地图方法封装

/*** 初始化地图*/
export const initMap = (dom: any) => {window.maptalksMap = new window.maptalks.Map(dom, mapOptions)
}

2）初始化底图

/*** 初始化底图*/
export const initBaseLayer = () => {const baseLayer = new window.maptalks.TileLayer(mapLayers.baseLayer, {urlTemplate: TianDiTuTile,subdomains: ['1', '2', '3', '4', '5'],attribution:'&copy; <a target="_blank" href="http://www.tianditu.cn">Tianditu</a>'})window.maptalksMap.setBaseLayer(baseLayer)
}

3）初始化底图的地点文字标记

/*** 初始化底图的地点文字标记*/
export const initBaseMarkLayer = () => {const baseMarkLayer = new window.maptalks.TileLayer(mapLayers.baseMarkLayer, {urlTemplate: TianDiTuMark,subdomains: ['1', '2', '3', '4', '5']})baseMarkLayer.addTo(window.maptalksMap)
}

4）设置半透明遮罩层mask，其中，maskGeoJSon为导出的高德数据

/*** 设置半透明遮罩层mask*/
export const initMaskPolygonLayer = () => {const maskPolygonLayer = new window.maptalks.VectorLayer(mapLayers.maskLayer)const geojson: any = maskGeoJSon.features[0].geometryconst wgsJson = gcoord.transform(geojson, gcoord.GCJ02, gcoord.WGS84);const polygons = window.maptalks.GeoJSON.toGeometry(wgsJson,(geometry: any) => {geometry.setSymbol({lineColor: '#01e0f1',lineWidth: 4,lineOpacity: 0.4,polygonFill: '#014493',polygonOpacity: 0.3})})maskPolygonLayer.addGeometry(polygons)maskPolygonLayer.addTo(window.maptalksMap)
}

5）设置覆盖物-某区域轮廓

/*** 设置覆盖物-嘉善轮廓*/
export const initAreaPolygonLayer = () => {const areaPolygonLayer = new window.maptalks.VectorLayer(mapLayers.areaPolygonLayer)const polygons = window.maptalks.GeoJSON.toGeometry(jiashanGeoJSon,(geometry: any) => {geometry.setSymbol({lineColor: '#01e0f1',lineWidth: 4,lineOpacity: 1,polygonFill: '#0e4d96',polygonOpacity: 0.8})})areaPolygonLayer.addGeometry(polygons)areaPolygonLayer.addTo(window.maptalksMap)
}

6）设置地名

/*** 设置地名*/
export const initAreaNameLayer = () => {const areaNameLayer = new window.maptalks.VectorLayer(mapLayers.areaNameLayer)jiashanTownCenter.forEach(item => {new window.maptalks.Marker(item.position, {symbol: {textName: item.name,textSize: 20,textFill: '#ccc'}}).addTo(areaNameLayer)})areaNameLayer.addTo(window.maptalksMap)
}

4.应用

useEffect(() => {if (amapDomRef.current) {initMap(amapDomRef.current) // 初始化地图initBaseLayer() // 初始化底图initBaseMarkLayer() // 初始化底图的地点文字标记// initBackgroundLayer()initMaskPolygonLayer() // 设置半透明遮罩层maskinitAreaPolygonLayer() // 设置覆盖物-区域(某地区)轮廓initAreaNameLayer() // 设置地名const data: any[] = getAllRealSchoolByMap().map(c => {return {name: c.title,position: c.position,status: c.checkStatus}})setCampusSecurySchoolMarkerToMap(data) // 业务数据点}}, [amapDomRef])

运行效果：不理想，出现了白色间隙，后面找出原因是因为高德地图和天地图不是同个坐标系（因为高德地图是火星坐标，而天地图是wgs84墨卡托4490），所以从高德地图上拉取的数据在天地图上不能完全适配，就出现了这样的间隙。

高德：火星坐标

天地图：wgs84墨卡托4490

解决方案：用gcoord进行坐标转换，参考文章：高德地图更换天地图底图（坐标转换）—使用高德API（WMTS）_高德经纬度转天地图经纬度_❄️文宸er的博客-CSDN博客

const wgsJson = gcoord.transform(geojson, gcoord.GCJ02, gcoord.WGS84);

最后，附上接口文档

MapTalks手册：https://doc.maptalks.com/docs/style/symbols/