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

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//量测

function measutreLength() {

toolbar.activate(esri.toolbars.Draw.POLYLINE);

}

function measutreArea() {

toolbar.activate(esri.toolbars.Draw.POLYGON);

}

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//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");