按照这个例子:http : //andywoodruff.com/blog/simple-shapefile-drawing-in-actionscript-3/ 我正在尝试创建一个世界地图,类似于 jqvmap。6 这是我的结果: http: //www.prestitiprotestati.info/test/Test.html
现在我需要创建一个更逼真的地图,在这个平面世界地图上添加一些投影。
我正在学习来自http://vis4.net/blog/posts/rendering-world-maps-in-as3/的教程,但是当我尝试创建投影时出现一个奇怪的错误,我无法理解来自哪里.
这是我的尝试:
private function onShapefile( event:Event ) : void
{
// use the ShpTools class to parse the shapefile into an array of records
var records : Array = ShpTools.readRecords(event.target.data).records;
// create a feature (point, polyline, or polygon) from each record
/*for each( var record : ShpRecord in records ){
var feature : ShpFeature = createFeature(record);
if ( feature != null ) features.push( feature );
}*/
var record:ShpRecord, poly:ShpPolygon, coords:Array, pt:ShpPoint, o:Point;
var polygons = [];
var bounds = new Rectangle();
for each (record in records) {
if (record.shapeType == ShpType.SHAPE_POLYGON) {
poly = record.shape as ShpPolygon;
for each (coords in poly.rings) {
var out:PointSet = new PointSet;
for each (pt in coords){
trace("PT.X: "+ObjectUtil.toString(pt.x));
if (projection.testPointDeg(pt.x, pt.y)) {
o = projection.project(deg2rad(pt.x), deg2rad(pt.y), new Point());
o.y *= -1;
out.push(o);
}
}
var out_poly:Polygon = new Polygon(out);
polygons.push(out_poly);
bounds = bounds.union(out_poly.boundingBox);
}
}
}
shpLoaded = true;
// draw the features
drawMap();
// to signal the completion of map loading/drawing
dispatchEvent(new Event("map loaded",true));
}
public function deg2rad(deg:Number):Number
{
return deg * Math.PI / 180.0;
}
我得到的错误来自这一行:
if (projection.testPointDeg(pt.x, pt.y))
错误是:
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at com.cartogrammar.shp::ShpMap/onShapefile()
[E:\FlashBuilder\Cartogrammar\src\com\cartogrammar\shp\ShpMap.as:96]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at flash.net::URLLoader/onComplete()
你可以帮帮我吗?