ArcGIS 4.11学习笔记之绘制扇形区域

最近都在思考如何做一个扇形形状的图形。毕竟这个图形官方没有直接绘制的API，而且在地图方面也会用到。所以在查询一番资料后，将自己的实现记录下来。

实现效果图：

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绘制扇形的函数。参考此文章:arcgis for js画扇形并给它填充不同的颜色后而实现。

function getPoints(center, radius, startAngle, endAngle, pointNum) {
    var sin, cos, x, y, angle;
    var points = [];
    points[0] = center;
    for(var i = 1; pointNum && i <= pointNum; i++) {
        angle = startAngle + (endAngle - startAngle) * i / pointNum;
        sin = Math.sin(angle * Math.PI / 180);
        cos = Math.cos(angle * Math.PI / 180);
        x = center[0] + radius * sin;
        y = center[1] + radius * cos;
        points[i] = [x, y];
    }
    points[points.length] = points[0];
    return points;
}

获取点与扇形中心点间的夹角

function getAngle4(x1, y1, x2, y2) {
    if(x1 == x2 && y1 == y2) {
        return -1;
    }
    var x = Math.abs(x1 - x2);
    var y = Math.abs(y2 - y1);
    var z = Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2));
    var cos = y / z;
    var radina = Math.acos(cos); //用反三角函数求弧度
    var angle = Math.floor(180 / (Math.PI / radina)); //将弧度转换成角度

    if(x2 >= x1 && y2 < y1) { //在第2象限
        angle = 180 - angle;
    } else if(x2 < x1 && y2 <= y1) {
        angle = 180 + angle;
    } else if(x2 <= x1 && y2 > y1) {
        angle = 363 - angle;
    }
    return angle;
};

有了构建扇形的点数组，构建ArcGISMap的polygon对象，接着生成Graphic对象加入到图层中显示

var secPoints = getPoints([113.190248,23.03], 0.01, 40, 90, 100);
var sectorSym = {
    type: "simple-fill",
    style: "solid",
    color: [255, 0, 0, 0.3],
    outline: {
        width: "0.5px",
        color: [255, 0, 0]
    }
}
var polygon = new Polygon({
    rings: secPoints
});
var sectorGrp = new Graphic(polygon, sectorSym, {
    "lon": 12,
    "lat": 444,
    "name": 5555
});
sectorLayer.add(sectorGrp) //加入图层

以上就是绘制扇形的关键方法。有问题和不足之处请多多指出。

demo地址:https://download.csdn.net/download/lf5566fl/11665249