Category: Geodesy

Spherical trig, Research Triangle, and Mathematica

This post will look at the triangle behind North Carolina’s Research Triangle using Mathematica’s geographic functions. Spherical triangles A spherical triangle is a triangle drawn on the surface of a sphere. It has three vertices, given by points on the sphere, and three sides. The sides of the triangle are portions of great circles running […]

Ellipsoid distance on Earth

To first approximation, Earth is a sphere. But it bulges at the equator, and to second approximation, Earth is an oblate spheroid. Earth is not exactly an oblate spheroid either, but the error in the oblate spheroid model is about 100x smaller than the error in the spherical model. Finding the distance between two points […]