修改面积函数的无法使用的问题

src/core/math/area.js

@@ -5,21 +5,14 @@
 
 import Transform from '../transform/Transform'
 
-const { Cesium } = DC.Namespace
-
 export default function area(positions) {
   let result = 0
   if (positions && Array.isArray(positions)) {
     let h = 0
-    let ellipsoid = Cesium.Ellipsoid.WGS84
-    let positions = [...positions].concat(positions[0])
-    for (let i = 1; i < positions.length; i++) {
-      let oel = ellipsoid.cartographicToCartesian(
-        Transform.transformWGS84ToCartographic(positions[i - 1])
-      )
-      let el = ellipsoid.cartographicToCartesian(
-        Transform.transformWGS84ToCartographic(positions[i])
-      )
+    let pos = positions.concat(positions[0])
+    for (let i = 1; i < pos.length; i++) {
+      let oel = Transform.transformWGS84ToCartesian(pos[i - 1])
+      let el = Transform.transformWGS84ToCartesian(pos[i])
       h += oel.x * el.y - el.x * oel.y
     }
     result = Math.abs(h).toFixed(2)