Linear distance between two points of cesium

Be careful ： If you calculate the plane distance between two points , Let the height of two points be zero

The format of the point ：

start_point = {
    
	lon: ' longitude ',
	lat: ' latitude ',
	height: ' high ',
}

Code ：

//  Calculate the straight-line distance before two points according to longitude and latitude 
function two_points_distance(start_point, end_point) {
    
  //  Longitude and latitude are converted into world coordinates 
  var start_position = Cesium.Cartesian3.fromDegrees(start_point.lon, start_point.lat, start_point.height);
  var end_position = Cesium.Cartesian3.fromDegrees(end_point.lon, end_point.lat, end_point.height);
  //  Returns the distance between two coordinates （ Company ： rice ）
  return Cesium.Cartesian3.distance(start_position, end_position);
}