如何在带有Google地图的openlayers中取消投影和重新投影多边形的顶点

Question

我想重新投影多边形的顶点。 我已经能够在边界范围内实现这一点，但是在顶点上却遇到了一些麻烦。

           function onFeatureModified(event) {
           var bounds = event.feature.geometry.getBounds();
           var answer = "bottom: " + bounds.bottom + "\n";
           answer += "left: " + bounds.left + "\n";
           answer += "right: " + bounds.right + "\n";
           answer += "top: " + bounds.top + "\n";
           alert(answer);

           var mapProjv =  map.getProjectionObject();
           var epsg4326v = new OpenLayers.Projection("EPSG:4326");
       var verticesNative = event.features[0].geometry.getVertices();
       var verticesLatLon = verticesNative.transform( mapProjv , epsg4326v  );
       var vertices = verticesNative;
           alert(verticesNative);
           }

下面的代码有效：

           var vertices = event.features[0].geometry.getVertices();
           alert(vertices);

Answer 1

getVertices()方法返回一个OpenLayers.Geometry.Point对象数组，因此您不能在其上调用transform()方法。 相反，您应该做的是遍历数组，并像这样对每个对象调用transform() ：

var vertices = event.features[0].geometry.getVertices();
var transformedVertices = [];
for(var i=0; i < vertices.length; i++){
    transformedVertices.push(vertices[i].transform(
        new OpenLayers.Projection("EPSG:900913"),
        new OpenLayers.Projection("EPSG:4326")
    ));
}

//create new feature with transformed vertices