这次我们用d3.js 来构建可视化
首先我们 定义一些坐标转换的工具方法
toScreen 方法
```javascript
//构建arcgis 的mapView
let view = mapView
toScreen(coordinate) {
- let coordinateType = getXYType(coordinate[0],coordinate[1]);
- let coordXY = getRealXY(coordinate[0],coordinate[1],coordinateType);
- let item = {
- x: coordXY.x,
- y: coordXY.y,
- spatialReference: view.spatialReference
- };
- let screenPoint = view.toScreen(item);
- return screenPoint;
};
getRealXY (x,y,xyType){
if(view.spatialReference.wkid === 4326 || view.spatialReference.wkid === 4490){
if(xyType == 'WGS84') {
return {
x: x,
y: y
}
} else {
return getLngLat(x,y);
}
} else if(view.spatialReference.wkid === 102100){
if(xyType == 'Mercator') {
return {
x: x,
y: y
}
} else {
return getMercator(x,y);
}
}
return {
x: x,
y: y
}
}
getXYType(x,y){
if(x <= 180 && y <= 90){
return "WGS84"
}else{
return "Mercator"
}
}