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，费了非常长的时间，各种调式找不到原因。

如今成功完毕。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，须要进行投影变换！由于一般咱们的底图坐标系为4326

//量測

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);

    //清除上一次的绘图内容

    myMap.graphics.clear();

    myMap.graphics.add(graphic);

    //进行投影转换，完毕后调用projectComplete

    MeasureGeometry(geometry);

}

//投影转换完毕后调用方法

function MeasureGeometry(geometry) {

    //假设为线类型就进行lengths距离測算

    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);

    }

    //假设为面类型须要先进行simplify操作在进行面积測算

    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);

    }

}

//显示測量距离

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("距离測量");

    myMap.infoWindow.setContent(" 測 量 长 度 ： <strong>" + parseInt(String(result.lengths[0])) + "米</strong>");

    myMap.infoWindow.show(CurPos);

}

//显示測量面积

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("面积測量");

    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");

}