(转载)ArcGIS Flex API配合LibertyGISI加载SHP文件

本文转载自《使用LibertyGIS在Flex中加载Shape数据》http://www.dancecoder.com/2012/255.html和《ArcGIS
Flex API加载SHP文件》http://www.gisall.com/html/66/102766-4308.html

某些情况下，如果在WebGIS系统中能够加载本地Map数据，会给用户带来很大的方便。SHP是使用范围很广泛的数据格式，而且数据结构早已公开，已经存在很多能够对SHP文件进行读取操作的类库。我们今天借助LibertyGIS（http://www.libertyvanguard.com/，一个开源的Flex
GIS Framework）来实现在浏览器端加载SHP数据。

首先来介绍下LibertyGIS，LibertyGIS是开源的shape数据展现框架（LibertyGIS
is an open source flex mapping framework for displaying ShapeFiles），官网地址：http://code.google.com/p/liberty-gis/；该框架包括一个独立的Map对象（com.liberty.controls.Map）以及加载shape文件所需的shp文件相关对象（
com.liberty.files.dbf.DBF; com.liberty.files.shapefile.ShapeFile），此外，LibertyGIS还提供了一个图层对象DataLayer（com.liberty.core.DataLayer）和自己的MapEvent事件。使用LibertyGIS能够很容易的展现我们客户端的shp数据。

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600"
xmlns:local="*" xmlns:esri="http://www.esri.com/2008/ags"
xmlns:shapefile="com.liberty.files.shapefile.*">
<fx:Script>
<![CDATA[
import com.esri.ags.Graphic;
import com.esri.ags.SpatialReference;
import com.esri.ags.geometry.MapPoint;
import com.esri.ags.geometry.Polygon;
import com.esri.ags.geometry.Polyline;
import com.esri.ags.utils.WebMercatorUtil;
import com.liberty.files.shapefile.IShapeFileContent;
import com.liberty.files.shapefile.ShapeFileRecord;

import mx.collections.ArrayCollection;
import mx.controls.Alert;
private var sps:SimpleMarkerSymbol=new SimpleMarkerSymbol();
private var sls:SimpleLineSymbol=new SimpleLineSymbol("solid");
private var sfs:SimpleFillSymbol=new SimpleFillSymbol("solid",0xff0000,0.7,sls);
private function loadShpData():void
{
shpFile.source="assets/data/cities.shp";
}

private function shpFileLoadComplete(event:Event):void
{
var graphics:ArrayCollection=new ArrayCollection();
var records:Array=shpFile.records;
for (var i:int=0; i < records.length; i++)
{
var record:ShapeFileRecord=records[i];
var content:IShapeFileContent=record.content;
var points:Vector.<Number>=content.getPoints();

switch(shpFile.type)
{
case 1:
{
var mapPoint:MapPoint=new MapPoint(points[0], points[1],new SpatialReference(4326));
if(map.spatialReference.wkid!=4326)
{
mapPoint=WebMercatorUtil.geographicToWebMercator(mapPoint) as MapPoint;
}
var graphic:Graphic=new Graphic(mapPoint);
graphic.symbol=sps;
graphics.addItem(graphic);
graphicsLayer.add(graphic);
break;
}
case 3:
{
var pArrLine:Array=new Array();
for(var j:Number=0;j<points.length;j+=2)
{
var point:MapPoint=new MapPoint(points[j],points[j+1],new SpatialReference(4326));
if(map.spatialReference.wkid!=4326)
{
point=WebMercatorUtil.geographicToWebMercator(point) as MapPoint;
}
pArrLine.push(point);
}
var polyline:Polyline=new Polyline();
polyline.addPath(pArrLine);
var grPolyline:Graphic=new Graphic(polyline);
grPolyline.symbol=sls;
graphics.addItem(grPolyline);
graphicsLayer.add(grPolyline);
break;
}
case 5:
{
var pArrPolygon:Array=new Array();
for(var k:Number=0;k<points.length-1;k+=2)
{
var pPoint:MapPoint=new MapPoint(points[k],points[k+1],new SpatialReference(4326));
if(map.spatialReference.wkid!=4326)
{
pPoint=WebMercatorUtil.geographicToWebMercator(pPoint) as MapPoint;
}
pArrPolygon.push(pPoint);
}
var polygon:Polygon=new Polygon();
polygon.addRing(pArrPolygon);
var grPolygon:Graphic=new Graphic(polygon);
grPolygon.symbol=sfs;
graphics.addItem(grPolygon);
graphicsLayer.add(grPolygon);
break;
}
default:
{
Alert.show("LibertyGIS不支持您的数据格式！","提示");
return;
}
}
}
graphicsLayer.graphicProvider=graphics;
}

private function onShapeFileProgress(event:ProgressEvent):void
{
progressBar.setProgress((event.bytesLoaded / event.bytesTotal) * 100, 100);
progressBar.label=int(event.bytesLoaded / 1000).toString() + "K";
}
]]>
</fx:Script>
<fx:Declarations>
<shapefile:ShapeFile id="shpFile" complete="shpFileLoadComplete(event)"
progress="onShapeFileProgress(event)"/>
</fx:Declarations>
<esri:Map id="map">
<esri:ArcGISTiledMapServiceLayer
url="http://services.arcgisonline.com/ArcGIS/rest/services/ESRI_Imagery_World_2D/MapServer"/>
<esri:GraphicsLayer id="graphicsLayer">
<esri:symbol>
<esri:SimpleMarkerSymbol color="0xff0000" size="5">
<esri:outline>
<esri:SimpleLineSymbol color="0x000000"/>
</esri:outline>
</esri:SimpleMarkerSymbol>
</esri:symbol>
</esri:GraphicsLayer>
</esri:Map>
<mx:HBox width="100%" backgroundColor="0xff0000">
<s:Button label="Load SHP Data" click="loadShpData()"/>
<mx:ProgressBar id="progressBar" minimum="0" maximum="100" mode="manual" color="0xFFFFFF"
labelPlacement="right"/>
</mx:HBox>
</s:Application>

效果如下