Openlayers 3 使用ol.interaction.Draw时，我可以获得圆形几何体吗？

我正在用ol.interaction.Draw画一个圆

this.draw = new ol.interaction.Draw({
    source: this.vectorSource,
    type: 'Circle'
});

this.draw.on('drawend', function( evt ){
    // evt.feature have no geometry !!!
}

但是我怎样才能得到圆的几何图形或者任何告诉我如何再次画同一个圆的东西呢

OL3.0您可以创建/编辑特征，但不能创建/编辑圆

OL3.5您可以创建圆，但不能编辑

OL_Latest您也不能编辑圆：

如果我以后能重现同样的圆圈，我会很高兴。

差不多了

现在，我可以通过向draw InAction添加一个几何函数来重现“圆”

var geometryFunction = ol.interaction.Draw.createRegularPolygon(90);

    this.draw = new ol.interaction.Draw({
        source: this.vectorSource,
        type: 'Circle',
        geometryFunction: geometryFunction,
    });

这将为特征生成几何图形，以便我可以存储它并稍后再次加载它，但它不是一个真正的圆，它只是由一个90点的多边形组成。所以我不能把它编辑成一个圆

想知道这个几何体的半径吗

{"type":"Feature","geometry":{"type":"Polygon","coordinates":[[[-4804935.286197088,-2605909.2147242804],[-4804836.58537814,-2605831.0293000625],[-4804743.578928918,-2605746.149310523],[-4804656.719967494,-2605654.988282439],[-4804576.431661996,-2605557.9903431754],[-4804503.105168979,-2605455.6280569425],[-4804437.097727745,-2605348.4001225093],[-4804378.730919913,-2605236.8289435934],[-4804328.289102704,-2605121.458083764],[-4804286.018023582,-2605002.849618253],[-4804252.123622994,-2604881.581395582],[-4804226.771031053,-2604758.244222341],[-4804210.083763039,-2604633.4389848416],[-4804202.143117644,-2604507.773721655],[-4804202.987780893,-2604381.8606613115],[-4804212.613637674,-2604256.3132395847],[-4804230.973791778,-2604131.7431108924],[-4804257.978794381,-2604008.757168381],[-4804293.497079825,-2603887.954587199],[-4804337.355606593,-2603769.923905379],[-4804389.340700352,-2603655.2401565393],[-4804449.199094949,-2603544.462068375],[-4804516.639166305,-2603438.1293405974],[-4804591.332353169,-2603336.7600155673],[-4804672.914757844,-2603240.8479544464],[-4804760.988919055,-2603150.860431155],[-4804855.125748342,-2603067.2358558625],[-4804954.866620535,-2602990.3816390927],[-4805059.72560813,-2602920.672206864],[-4805169.19184868,-2602858.4471765244],[-4805282.732033666,-2602804.009702166],[-4805399.793006718,-2602757.6249976917],[-4805519.804458544,-2602719.5190447196],[-4805642.1817054115,-2602689.8774916218],[-4805766.328537677,-2602668.8447490656],[-4805891.640124453,-2602656.5232864586],[-4806017.505960285,-2602652.973132728],[-4806143.312839472,-2602658.211583866],[-4806268.447843544,-2602672.213118665],[-4806392.301327342,-2602694.909523055],[-4806514.269889141,-2602726.1902224356],[-4806633.759310369,-2602765.902820383],[-4806750.187450577,-2602813.8538411125],[-4806862.987083566,-2602869.809672071],[-4806971.608660867,-2602933.4977020747],[-4807075.522989073,-2603004.607649443],[-4807174.22380802,-2603082.793073661],[-4807267.230257243,-2603167.6730632004],[-4807354.089218667,-2603258.834091285],[-4807434.3775241645,-2603355.8320305482],[-4807507.704017182,-2603458.194316781],[-4807573.711458416,-2603565.4222512143],[-4807632.078266247,-2603676.99343013],[-4807682.520083456,-2603792.3642899594],[-4807724.791162578,-2603910.972755471],[-4807758.685563167,-2604032.240978142],[-4807784.038155108,-2604155.5781513825],[-4807800.725423122,-2604280.383388882],[-4807808.666068517,-2604406.0486520687],[-4807807.821405267,-2604531.961712412],[-4807798.195548487,-2604657.509134139],[-4807779.8353943825,-2604782.0792628312],[-4807752.83039178,-2604905.0652053426],[-4807717.312106336,-2605025.867786525],[-4807673.453579567,-2605143.8984683445],[-4807621.468485809,-2605258.5822171844],[-4807561.610091211,-2605369.3603053484],[-4807494.170019856,-2605475.693033126],[-4807419.4768329915,-2605577.0623581563],[-4807337.8944283165,-2605672.974419277],[-4807249.8202671055,-2605762.9619425684],[-4807155.683437819,-2605846.586517861],[-4807055.9425656255,-2605923.440734631],[-4806951.083578031,-2605993.1501668594],[-4806841.61733748,-2606055.375197199],[-4806728.077152494,-2606109.8126715575],[-4806611.016179442,-2606156.197376032],[-4806491.004727617,-2606194.303329004],[-4806368.627480749,-2606223.944882102],[-4806244.480648483,-2606244.977624658],[-4806119.169061707,-2606257.299087265],[-4805993.303225876,-2606260.8492409955],[-4805867.496346689,-2606255.610789858],[-4805742.361342616,-2606241.6092550587],[-4805618.507858818,-2606218.9128506687],[-4805496.539297019,-2606187.632151288],[-4805377.049875791,-2606147.9195533404],[-4805260.621735584,-2606099.968532611],[-4805147.822102594,-2606044.0127016525],[-4805039.200525293,-2605980.324671649],[-4804935.286197088,-2605909.2147242804]]]},"properties": null}

多边形的质心可以是圆心，我想。。。。此质心到边界中任何点的距离可以是半径。。。。我不知道如何使用JS获得这个

以中心为例：

this.draw.on('drawend', function( evt ){
    var aa = evt.feature.getGeometry().getExtent();
    var oo = ol.extent.getCenter(aa);
    console.log( oo );
});

---

现在我必须找到一种获取半径的方法。

要获得绘制的圆特征的中心和半径，请使用以下代码

this.draw.on('drawend', function( evt ){
    var geometry = evt.feature.getGeometry();
    var radius = geometry.getRadius();
    var center = geometry.getCenter();
    // .... your code
});

由于绘制了一个圆，因此几何体类型应为

ol.geom.circle

。 使用此几何体对象，可以使用

getRadius（）

和

getCenter（）

方法获得半径和中心。有关

ol.geom.Circle

的更多信息，请点击此链接

---

不要写几何函数，然后你可以使用上面的代码。完美！你真是个天才！谢谢。几何体类型为

GeometryCollection

。。。但它仍然有效。如果没有写入几何函数，则检查ol.geom.Circle的几何实例，它将返回true。这就是它起作用的原因。只有此类型支持这两种方法。