In a Cartesian coordinate system each point at a plane is associated with coordinates that are its abscissa and ordinate. To determine coordinates of point A you may drop perpendiculars on axis X and Y. In the movie a pilot of an airplane is making a picture of a town with 3 flags (points A, B, C). He determines a coordinate system and fix coordinates of the points A, B, C. An abscissa of the point A is 2 and its ordinate is 1.
