Issue No.02 - April-June (1981 vol.1)
Fall River Pass Quadrangle, Colorado. This image is a terrain model of a 6.6 x 8.5-mile area in Rocky Mountain National Park, near Estes Park, Colorado. A digital contour-line map of the quadrangle was converted into a hierarchical quadtree structure of bicubic surface patches. The image displays 4088 patches with first derivative continuity at the quadtree level. The view of the terrain, which in the area of the model ranges from 9000 to 12,500 feet, is from the south-southwest. The sun is at the southeast at 30 degrees. The ratio of the vertical scale to the horizontal scales is 7:1: 1, and vertical elevation colors from green to brown are painted on the terrain.
"Displays on Display", IEEE Computer Graphics and Applications, vol.1, no. 2, pp. 91, April-June 1981, doi:10.1109/MCG.1981.1673895