&gt;Not if you&#x27;re going to say the projection is flat. If the projection is flat, and the projection is the model, then I should be able to lay a flat ruler, appropriately scaled, between any two points on the flat map and read off the actual distance between those two points.<p>Is a constant distance metric part of the definition of flat? Why don&#x27;t the grid lines on the map count as an appropriately scaled ruler?