fix 修复例子报错

Author: chenxianhuii

examples/mapboxgl/ugc_isIntersectRegionWithRect.html

@@ -135,6 +135,7 @@ <h5 class="panel-title text-center">面与矩形相交检测</h5>
       }
 
       function search() {
+        clearLayer();
         let intersectCount;
         var geometryAnalysis = new mapboxgl.supermap.GeometryAnalysis();
         [polygon1, polygon2].forEach((polygon) => {
@@ -162,6 +163,16 @@ <h5 class="panel-title text-center">面与矩形相交检测</h5>
         });
       }
 
+      function clearLayer() {
+        if (!map) {
+          return;
+        }
+        if (map.getLayer('fill3')) {
+          map.removeLayer('fill3');
+          map.removeSource('fill3');
+        }
+      }
+
       initMap(url).then((map) => {
         addFeatures();
       });

examples/mapboxgl/ugc_pointPositon.html

@@ -257,6 +257,10 @@ <h5 class="panel-title text-center">点线关系</h5>
           map.removeLayer('line1');
           map.removeSource('line1');
         }
+        if (map.getLayer('nearestPoint')) {
+          map.removeLayer('nearestPoint');
+          map.removeSource('nearestPoint');
+        }
       }
       initMap(url).then((map) => {
         addFeatures();