Surveying on a Flat ERM
• The points A and B are on the ERM surface.
• The reference distance AB on the ERM is also the Euclidean distance from A to B in the coordinate frame.
• The normals at A and B are co-planar.
• The azimuth ? (or any angle) is readily defined.
• Note that z is not involved and chaining would be easy.
• By definition there is no terrain surface.