I have a point expressed in lat/long
Position louvreMuseum = new Position( 48.861622, 2.337474 );
and I have a radius value expressed in meters. I need to check if another point, also expressed in lat/long, is inside the circle.
If I were on a flat surface I can simply use the formula
(x - center_x)^2 + (y - center_y)^2 <= radius^2
as deeply explained in these SO answer.
However as per the latitude/longitude usage I can not use that formula because of the spherical nature of the planet.
How can I calculate a distance from any given point to the center to be compared with the radius?
Function to calculate the distance between two coordinates (converted to C# from this answer):
If the distance between the two points is less than the radius, then it is within the circle.