How to calculate the sphere surface distance between two points

[试试帆布鞋]

Click the mouse, get point(lat1,lon1)and point (lat2,lon2)
from globe , how to calculate the sphere surface distance between two points？
The earth is not a standard sphere，

[试试帆布鞋]

i view the source code globe.jshttps://github.com/NASAWorldWind/Web...globe/Globe.js,
there are two radius

/**
* This globe's equatorial radius.
* @type {Number}
* @default 6378137.0 meters
*/
this.equatorialRadius = 6378137.0;

/**
* This globe's polar radius.
* @type {Number}
* @default 6356752.3 meters
*/
this.polarRadius = 6356752.3;

[glueck]

The WebWorldWind class Location includes the following functions for calculating distance:

greatCirlceDistance
rhumbDistance
linearDistance

Each of these functions return the distance as an angle in radians, which then must be multiplied by the radius to get a "surface" distance.

The methods mentioned above assume a spherical earth.

[price5583]

Here are a couple of utility functions I wrote for the app I built that do that. Hope they help.

/*
* This function returns the distance in meters between two WorldWind.Locations (i.e. between two geographical lat-lon locations)
* This function uses the great circle method for determining distance and does not consider altitude.
*/
var DistanceInMetersBetweenTwoLocations = function(location1, location2)
{
var radius = 6378137.0; // radius of the world wind globe in meters
var distanceAsAngle = WorldWind.Location.greatCircleDistance(l ocation1, location2);
return distanceAsAngle * radius;
};


/*
* This function returns the distance in meters between two WorldWind.Positions (i.e. between two geographical lat-lon-alt positions)
* This function uses the great circle method for determining horizontal distance then also considers altitude into the distance using the Pythagorean theorem.
*/
var DistanceInMetersBetweenTwoPositions = function(position1, position2)
{
var location1 = Util.LocationFromPosition(position1);
var location2 = Util.LocationFromPosition(position2);

var alt1 = position1.altitude;
var alt2 = position2.altitude;

//So to include alt first we get the horizontal great circle distance (at the estimated surface of the earth's alt of 6378137)
var horizontalDistance = DistanceInMetersBetweenTwoLocations(loca tion1, location2);

//Now we get the distance of the difference in altitude
var heightDifferenceDistance = Math.abs(alt1-alt2);

//Now to include the alt distance also between our two positions also we simply use the Pythagorean theorem A^2 + B^2 = C^2
//Where A is the horizontal great circle distance and B is the distance of the difference in altitude which will result in c the distance between the two positions.
//A squared plus B squared equals c squared.
var aSquared = horizontalDistance * horizontalDistance; //Squares our horizontalDistance
var bSquared = heightDifferenceDistance * heightDifferenceDistance; //Squares our heightDifferenceDistance
var cSquared = aSquared + bSquared; //Calculates C which is the square of our distance

var c = Math.sqrt(cSquared); //Extracts C from C Squared which is our distance.

return c; //Returns the distance in meters between the two positions passed in
};