arcgis api for javascript 距离与面积量算

在之前的实验中，距离量算跟面积量算一直出问题，费了很长的时间，各种调式找不到原因。现在成功完成，与君共勉

1、距离量算中 lengthParams.polylines = [geometry];

2、面积量算中 this.outSR = new esri.SpatialReference({ wkid: 102113 });

geometryService.project([geometry], this.outSR, function (geometry) {

geometryService.simplify(geometry, function (simplifiedGeometries) {

areasAndLengthParams.polygons = simplifiedGeometries;

areasAndLengthParams.polygons[0].spatialReference = new esri.SpatialReference(102113);

geometryService.areasAndLengths(areasAndLengthParams);

});

});

还有面积量算中跟距离量算有所不同，需要进行投影变换！因为一般咱们的底图坐标系为4326

//量测
function measutreLength() {
toolbar.activate(esri.toolbars.Draw.POLYLINE);
}
function measutreArea() {
toolbar.activate(esri.toolbars.Draw.POLYGON);
}

//量算
function doMeasure(geometry) {
//更加类型设置显示样式
measuregeometry = geometry;
toolbar.deactivate();
switch (geometry.type) {
case "polyline":
var symbol = new esri.symbol.SimpleLineSymbol(esri.symbol.SimpleLineSymbol.STYLE_SOLID, new dojo.Color([0, 0, 0]), 2);
break;
case "polygon":
var symbol = new esri.symbol.SimpleFillSymbol(esri.symbol.SimpleFillSymbol.STYLE_NONE, new esri.symbol.SimpleLineSymbol(esri.symbol.SimpleLineSymbol.STYLE_DASHDOT, new dojo.Color([255, 0, 0]), 2), new dojo.Color([255, 255, 0, 0.25]));
break;
}
//设置样式
var graphic = new esri.Graphic(geometry,symbol);
//清除上一次的画图内容
myMap.graphics.clear();
myMap.graphics.add(graphic);
//进行投影转换，完成后调用projectComplete
MeasureGeometry(geometry);
}

//投影转换完成后调用方法
function MeasureGeometry(geometry) {
//如果为线类型就进行lengths距离测算
if (geometry.type == "polyline") {
var lengthParams = new esri.tasks.LengthsParameters();
lengthParams.polylines = [geometry];
lengthParams.lengthUnit = esri.tasks.GeometryService.UNIT_METER;
lengthParams.geodesic = true;
lengthParams.polylines[0].spatialReference = new esri.SpatialReference(4326);
geometryService.lengths(lengthParams);
dojo.connect(geometryService, "onLengthsComplete", outputDistance);
}
//如果为面类型需要先进行simplify操作在进行面积测算
else if (geometry.type == "polygon") {
var areasAndLengthParams = new esri.tasks.AreasAndLengthsParameters();
areasAndLengthParams.lengthUnit = esri.tasks.GeometryService.UNIT_METER;
areasAndLengthParams.areaUnit = esri.tasks.GeometryService.UNIT_SQUARE_METERS;
this.outSR = new esri.SpatialReference({ wkid: 102113 });
geometryService.project([geometry], this.outSR, function (geometry) {
geometryService.simplify(geometry, function (simplifiedGeometries) {
areasAndLengthParams.polygons = simplifiedGeometries;
areasAndLengthParams.polygons[0].spatialReference = new esri.SpatialReference(102113);
geometryService.areasAndLengths(areasAndLengthParams);
});
});
dojo.connect(geometryService, "onAreasAndLengthsComplete", outputAreaAndLength);
}
}

//显示测量距离
function outputDistance(result) {
var CurX = measuregeometry.paths[0][measuregeometry.paths[0].length - 1][0];
var CurY = measuregeometry.paths[0][measuregeometry.paths[0].length - 1][1];
var  CurPos  =  new  esri.geometry.Point(CurX,  CurY, myMap.spatialReference);
myMap.infoWindow.setTitle("距离测量");
myMap.infoWindow.setContent(" 测 量 长 度 ： <strong>" + parseInt(String(result.lengths[0])) + "米</strong>");
myMap.infoWindow.show(CurPos);
}

//显示测量面积
function outputAreaAndLength(result) {
var CurX = (measuregeometry._extent.xmax + measuregeometry._extent.xmin) / 2;
var CurY = (measuregeometry._extent.ymax + measuregeometry._extent.ymin) / 2
var CurPos = new esri.geometry.Point(CurX, CurY, myMap.spatialReference);
myMap.infoWindow.setTitle("面积测量");
myMap.infoWindow.setContent(" 面积 ： <strong>" + parseInt(String(result.areas[0])) + "平方米</strong> 周长：" + parseInt(String(result.lengths[0])) + "米");
myMap.infoWindow.show(CurPos);
//alert("面积：" + dojo.number.format(result.areas[0]) + "平方米" + " 长度：" + dojo.number.format(result.lengths[0]) + "米");
}