Development of procedures for the computerized plotting of a sun-path diagram, and shading mask protractor Conference Paper uri icon


  • The AIA's sun-path diagram and shading mask protractor are convenient ways of graphically displaying the effectiveness of a solar shading device. Unfortunately, most practicing solar architects and engineers still use photocopies of the sun-path diagrams that are provided in the AIA's Architectural Graphic Standards to accomplish their analysis. This paper describes the basic graphical equations that can be used to construct a shading mask protractor and sun-path diagram, and demonstrates their use with an example shading device at several latitudes. The equations that are presented can be used in a computer program to produce a complete sun-path diagram. The sun's path and shading routines can represent virtually and shading device at a given northern latitude. The entire diagram is produced efficiently with only a handful of simple equations by repeatedly looping though the mathematical relations to generate the necessary lines and curves. Paired ASCII output can then be fed to any graphics package to obtain a hard copy of the diagram.

author list (cited authors)

  • McWatters, K., & Haberl, J. S.

publication date

  • January 1994