Rudolf Rothe’s Darstellende Geometrie des Geländes applies descriptive geometry to the land itself: contour-line representation of terrain, gradients and profiles, cut-and-fill, and the constructions used by engineers and military surveyors to reason about ground they could draw but not yet walk.
It is applied geometry with mud on its boots, from the era when every road and railway began as a drawing. Download the free EPUB, in German, for the mathematics of landscape.