<i>&gt; The projection chosen IS the model</i><p>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. But I can&#x27;t do that; and the model knows I can&#x27;t do that. The model tells me to take the coordinates on the map of two points and plug them into a complicated mathematical formula if I want to get the actual distance between them. So the model is <i>not</i> flat in the sense that matters--in the predictions it makes for distances between points.