THE PROPORTIONAL RELIEF LANDFORM MAP1

THE problem of representing surface configuration in the plane of a map remains a major challenge to the cartographer. For many purposes, pictorial methods of terrain mapping have proved successful as a means of coping with this problem.2 Some useful techniques are available for the construction of pictorial terrain maps. The physiographic diagram of Lobeck, stressing structural influences in terrain formation, and the more refined landform map of Raisz,3 emphasizing the existing product of geomorphic processes, are splendid devices for orienting the viewer to the physiographic patterns of broad regions. Both techniques are based upon the use of symbols to represent general landform types and are designed for use in small-scale maps. Generally these maps are drawn at scales less than 1: 1,000,000. However, the map reader is often interested in detail which cannot be drawn into smallscale maps nor depicted by noncommensurable symbols. Robinson and Thrower have elaborated on a technique introduced by Tanaka Kitiro which utilizes "inclined traces" to preserve planimetry in the pictorial terrain map.4 This method is especially valuable for overlay work where continuous planimetry is essen-