An algorithm for automated digital rock drawing in the style used in Czech topographic maps

Anotace: The Land Survey Office of the Czech Republic developed a method for digital cliff drawing for use in the production of their large-scale topographic maps. At the core of this method is the process of filling a polygon with lines that resemble stylized hachures. As these lines are produced manually, this article aims at the automation of this process, and presents an algorithm for automated digital rock drawing. This algorithm was designed based on a previous detailed analysis of the problem, and experience supported by numerous examples found in maps. The individual steps of this algorithm, which was successfully tested on selected areas of various rocky terrains in the Czech Republic, are described in detail. The results of the tests are assessed, and the pros, cons and limitations of the algorithm are discussed.