(转)Arcgis for Js之GeometryService实现测量距离和面积
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http://blog.csdn.net/gisshixisheng/article/details/40540601
距离和面积的测量时GIS常见的功能,在本节,讲述的是通过GeometryService实现测量面积和距离。先看看实现后的效果:
距离 面积
首先,进行配置:
- //identify proxy page to use if the toJson payload to the geometry service is greater than 2000 characters.
- //If this null or not available the project and lengths operation will not work. Otherwise it will do a http post to the proxy.
- esriConfig.defaults.io.proxyUrl = "/proxy";
- esriConfig.defaults.io.alwaysUseProxy = false;
接着,定义GeometryService和绘图工具:
- var gsvc = new GeometryService("http://localhost:6080/arcgis/rest/services/Utilities/Geometry/GeometryServer");
- var measureToolbar = new esri.toolbars.Draw(map);
接下来,绘图结束后将所绘制图形添加到地图上面,并返回测量结果,那么增加measureToolbar的draw-end事件:
- measureToolbar.on("draw-end",showMeasureResults);
- /**
- * 显示测量结果
- * @param evt
- */
- var showPt=null;
- function showMeasureResults(evt){
- measureToolbar.deactivate();
- map.setMapCursor("default");
- var geometry = evt.geometry;
- switch (geometry.type) {
- case "polyline":{
- var length = geometry.paths[0].length;
- showPt = new Point(geometry.paths[0][length-1],map.spatialReference);
- var lengthParams = new LengthsParameters();
- lengthParams.lengthUnit = esri.tasks.GeometryService.UNIT_KILOMETER;
- lengthParams.polylines = [geometry];
- gsvc.lengths(lengthParams);
- break;
- }
- case "polygon":{
- showPt = new Point(geometry.rings[0][0],map.spatialReference);
- var areasAndLengthParams = new AreasAndLengthsParameters();
- areasAndLengthParams.lengthUnit = esri.tasks.GeometryService.UNIT_KILOMETER;
- areasAndLengthParams.areaUnit = esri.tasks.GeometryService.UNIT_SQUARE_KILOMETERS;
- gsvc.simplify([geometry], function(simplifiedGeometries) {
- areasAndLengthParams.polygons = simplifiedGeometries;
- gsvc.areasAndLengths(areasAndLengthParams);
- });
- break;
- }
- }
- var graphic = new Graphic(geometry, getGeometrySymbol(geometry.type));
- map.graphics.add(graphic);
- }
根据geometry的类型,增加GeometryService的lengths-complete或者areas-and-lengths-complete事件:
- gsvc.on("lengths-complete",outputLength);
- function outputLength(evtObj){
- var result = evtObj.result;
- showmeasureInfo(showPt, result.lengths[0].toFixed(3), "千米");
- };
- gsvc.on("areas-and-lengths-complete",outputAreaAndLength);
- function outputAreaAndLength(evtObj){
- var result = evtObj.result;
- showmeasureInfo(showPt, result.areas[0].toFixed(3), "平方千米");
- };
最后,将返回的结果显示在地图上:
- /**
- * 显示测量结果
- * @param showPnt
- * @param data
- * @param unit
- */
- function measureInfo(showPnt,data,unit){
- var measureDiv=$("#measure");
- var isShow = false;
- var screenPnt=map.toScreen(showPnt);
- measureDiv.css("left",screenPnt.x+"px");
- measureDiv.css("top",screenPnt.y+"px");
- measureDiv.css("position","absolute");
- measureDiv.css("height","20px");
- measureDiv.css("display","block");
- isShow = true;
- measureDiv.css("z-index","999");
- if(unit==="千米"){
- measureDiv.css("width","90px");
- }
- else{
- measureDiv.css("width","130px");
- }
- $("#result").html(data+unit);
- $("#infoclose").click(function(){
- map.graphics.clear();
- measureDiv.css("display","none");
- isShow = false;
- });
- map.on("pan-start", function(){
- measureDiv.css("display","none");
- });
- map.on("pan-end", function(panend){
- if(isShow == true){
- screenPnt=map.toScreen(showPnt);
- measureDiv.css("left",screenPnt.x+"px");
- measureDiv.css("top",screenPnt.y+"px");
- measureDiv.css("position","absolute");
- measureDiv.css("height","20px");
- measureDiv.css("display","block");
- }
- });
- map.on("zoom-start", function(){
- measureDiv.css("display","none");
- });
- map.on("zoom-end", function(){
- if(isShow == true){
- screenPnt=map.toScreen(showPnt);
- measureDiv.css("left",screenPnt.x+"px");
- measureDiv.css("top",screenPnt.y+"px");
- measureDiv.css("position","absolute");
- measureDiv.css("height","20px");
- measureDiv.css("display","block");
- }
- });
- };
结果的显示我是通过一个div来显示的,并且做了缩放和地图移动的处理。
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