Getting Real: Reflecting on the New Look of National Park Service Maps
U.S. National Park Service
Division of Publications
P.O. Box 50 Fillmore St.
Harpers Ferry, WV, USA 25425-005
The U.S. National Park Service (NPS) is now designing 2D tourist maps, primarily of mountainous areas, with enhanced realism akin to that found on geo-images (aerial photographs and satellite images). Unlike the venerable aerial photograph map, which consists of labels and vector elements placed on a raster background image, the NPS design approach- emphasizes cartographic elements over geo-imagery. On an otherwise ordinary map, bits and pieces of geo-images are selectively inserted as placed raster art (often merged with the shaded relief) to add natural textures. The result is a reconstituted hybrid that brings the best traits of geo-images -- their often eye-catching beauty, realism, rich textures, and tiny details that readers find so fascinating -- to the familiar format of a map (example). Through manipulation in Adobe Photoshop, the cartographically unsuitable traits found in most geo-images are minimized or eliminated. These traits include relief inversion caused by southeast illumination, dense cast shadows thrown by tall peaks that obscure land surface details, and too much and/or inappropriate raw image data that overwhelms the reader.
Among the aerial photograph-inspired map design techniques to be discussed are:
--Texture optimization: Textures, cloned from geo-images or synthetically generated, are swapped into landcover classifications precisely defined on other geo-images. For example, a forest canopy texture cloned from an aerial photograph from, say California, might be used to depict forest cover on a map of Alaska. Also, texture-generated rock hachuring, similar to that used on Swiss topographic maps for cliff depiction, is used.
--Aquafication: Drainage and water bodies are depicted with rasterized vectors that are merged with underlying geo-images and shaded relief. Artificially-generated sun glints, wave patterns, surf breaks, and stream tapering are used.
--Illuminated shaded relief: Visible illumination is used to enhance the illusion of three-dimensionality, lighten the overall density of relief, and depict alpenglow in high mountain regions.
Within the context of the debate over the advantages of strictly cartographic (abstract) versus aerial photographic (realistic) symbolization, my paper argues that the choice need not be either/or. The design ideas espoused in my paper have been rarely used in the pre-digital era because of the inadequate tools available to cartographers at that time. It is inevitable that photorealistic map design will gain in popularity as digital cartography matures. It is now technically feasible. Moreover, photorealistic maps are, arguably, more attractive and understandable, especially for the casual users of tourist maps.