Latitude-longitude coordinate range given radius

[moonman239]

Hello,

Is there a formula for calculating a range of latitude-longitude coordinates within a certain radius of a given point? Using ellipsoidal geometry, preferably.

 

[SonyAD]

Let the given point on the sphere be of (α,β) longitude and latitude.

Let θ be the angle between (α,β) and the radius around it.

What you need to do is traverse φ through a full rotation:

longitude = α + arcsin( cos(φ) · sin(θ) )
latitude = β + arcsin( sin(φ) · sin(θ) )

these would work equally well

longitude = α + arcsin( sin(φ) · sin(θ) )
latitude = β + arcsin( cos(φ) · sin(θ) )