Cartesian3.distance - 返回NaN？(Cartesian3.distance - returning NaN?)

 我试图找到鼠标点击和最近的一组广告牌之间的距离。 我的代码如下： 
 
var smallestDistance = -1;
var currentDistance = -1;
var nearestPeak;
var peakPosition;
var mousePosition = new Cesium.Cartesian3(ev.clientX, ev.clientY, 0.0);
for (var i = 0; i < peaks.length; i++) {
    peakPosition = peaks[i].position;
    currentDistance = Cesium.Cartesian3.distance(mousePosition, peakPosition);
    console.log( 'CESIUM: Distance to ' + peaks[i].name + ': ' + currentDistance + ' units.' );
    if (currentDistance < smallestDistance) {
        smallestDistance = currentDistance;
        nearestPeak = displayedPeaks[i];
    }
}
console.log( 'CESIUM: nearest peak is peak ' + nearestPeak.peakId );
if (smallestDistance != -1 && smallestDistance < 100000) {
    selectedPeak = nearestPeak;
}
 
 问题出现在第一个console.log语句中，它显示在： 
 
CESIUM: Distance to peak 1: NaN units.
 
 根据铯的文件，它应该返回一个数字。 我可以发誓我在过去的项目中做了类似的事情，并没有这个问题。 我有强烈的怀疑，我失踪和/或忘记了一些非常基本的东西。 任何人都可以建议吗？ 
 
 编辑：我做了一些进一步的调试，我发现peakPosition.x和peakPosition.y都是未定义的，其中peakPosition = peak [i] .position。 peak [i]仍然在地球上渲染为广告牌，而peakPosition是一个对象。 根据Cesium文档，它应该是Cartesian3类型的对象，它应该有x和y成员。 那么为什么这些成员是不确定的？ 
 
 编辑2：我试图更换这一行： 
 
peakPosition = peaks[i].position;
 
 有了这个： 
 
peakPosition = new Cesium.Cartesian3(this.peaks[i].position.x, this.peaks[i].position.y, 0.0);
 
 并且它的x，y和z成员总是0,0和0.我无法想象出我的生活。 

I'm trying to find the distance between a mouseclick and the nearest of a set of billboards. My code is as follows:
 
var smallestDistance = -1;
var currentDistance = -1;
var nearestPeak;
var peakPosition;
var mousePosition = new Cesium.Cartesian3(ev.clientX, ev.clientY, 0.0);
for (var i = 0; i < peaks.length; i++) {
    peakPosition = peaks[i].position;
    currentDistance = Cesium.Cartesian3.distance(mousePosition, peakPosition);
    console.log( 'CESIUM: Distance to ' + peaks[i].name + ': ' + currentDistance + ' units.' );
    if (currentDistance < smallestDistance) {
        smallestDistance = currentDistance;
        nearestPeak = displayedPeaks[i];
    }
}
console.log( 'CESIUM: nearest peak is peak ' + nearestPeak.peakId );
if (smallestDistance != -1 && smallestDistance < 100000) {
    selectedPeak = nearestPeak;
}
 
The issue appears in the first console.log statement, where it displays:
 
CESIUM: Distance to peak 1: NaN units.
 
According to Cesium's documentation, it should be returning a number. I could swear I did something similar in a past project and didn't have this issue. I have a strong suspicion that I am missing and/or forgetting something very basic. Can anyone advise?
 
EDIT: I did some further debugging, and I am finding that peakPosition.x and peakPosition.y are both undefined, where peakPosition = peaks[i].position. peaks[i] is still rendering as a billboard on the globe, and peakPosition is an object. According to the Cesium documentation, it SHOULD be an object of type Cartesian3, which should have x and y members. So why would those members be undefined?
 
EDIT 2: I tried replacing this line:
 
peakPosition = peaks[i].position;
 
with this:
 
peakPosition = new Cesium.Cartesian3(this.peaks[i].position.x, this.peaks[i].position.y, 0.0);
 
and its x, y, and z members are always 0, 0, and 0. I can't figure this out for the life of me.

原文：https://stackoverflow.com/questions/46837189