Coordinates for "earth" - the sphere
Coordinates for the torus!
Activity for maps on Torus.
Locate P and Q on the map! give their coordinates.
Maps of the earth that use Projection:
What is projection for Flatland?
Center of projection/ perspective.
[ compare with similarity].
Correspondences: Activity:Circle to Line:
How to see the Infinite using Projective geometry.
Circle to line and line to Circle!
Line to Line