Distance

CesiumJS
1

Hello! I am very new to Cesium and am in need of help with a distance function. The way I would set this up is by using a post I found previously by Hypersonic with this distance function:

var viewer = new Cesium.Viewer('cesiumContainer');
var geodesic = new Cesium.EllipsoidGeodesic();
var cart1 = new Cesium.Cartographic(80,40);
var cart2 = new Cesium.Cartographic(90,50);
geodesic.setEndPoints(cart1, cart2);
console.log(geodesic.surfaceDistance);

Instead of using set points I would like to get the points by a combination of mouse click and press of a keyboard button, but nothing seems to be working. The code I have currently is

if (Cesium.ScreenSpaceEventType.Right_Click && flags.one)
{
window.alert(message);
}

Cesium is still not responding to this, but my experience with this and javascript is minimal so any help would be great thanks!

2

I’m not sure in what context you are calling that if block, but it’s incorrect. Here’s a small complete example you can paste into sandcastle that spits out the surface distance whenever 2 right clicks are made. You can add a KeyboardEventModifier as an extra parameter after the RIGHT_CLICK if you want to require shift/ctrl/alt. For example KeyboardEventModifier.SHIFT. It should be straightforward to enhance this code to create a point/line on each click for visual feedback.

var viewer = new Cesium.Viewer(‘cesiumContainer’);

var scene = viewer.scene;

var ellipsoid = scene.globe.ellipsoid;

var handler;

var positions = ;

// Mouse over the globe to see the cartographic position

handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);

handler.setInputAction(function(movement) {

var cartesian = viewer.camera.pickEllipsoid(movement.position, ellipsoid);

if (cartesian) {

var cartographic = ellipsoid.cartesianToCartographic(cartesian);

positions.push(cartographic);

if(positions.length === 2) {

var geodesic = new Cesium.EllipsoidGeodesic(positions[0], positions[1]);

console.log(geodesic.surfaceDistance.toFixed(2) + ’ m’);

positions.length = 0;

}

}

}, Cesium.ScreenSpaceEventType.RIGHT_CLICK);

3

Thank you this works great, I am trying to figure out how to apply this to areas off the earth as well and to automatically update for a tracked moving object like a satellite, is that currently a feature possible in Cesium?

4

If you want to track off-earth distance you would want to use straight-line Cartesian3.distance rather than EllipsoidGeodesic. Other than that, it should be pretty straight forward to adapt this code to handle the cases you want.