Relief shown by 1.5 m and 20 m countours. Aerial photogrammetric survey of Medellín was done by Cartesian projection originated on Las Cruces No. 6 with Gauss coordinates, point of origin located in the Observatorio Astronómico de Bogotá with adjustments. "Plano presentado al VIII Congreso Nacional de Ingeniería, Area Urbana de Medellin." "Fotografías tomadas en Septiembre de 1966."