3D Map Presentation A Systematic Evaluation of Important Graphic Aspects
Institute of Cartography
Swiss Federal Institute of Technology (ETH Zurich)
Phone: ++41 / 1 / 633 30 29
Fax: ++41 / 1 / 633 11 53
With reasonably accurate digital terrain models (DTM) and sophisticated software packages for their visualisation, impressive analytical perspective views of landscape models can be created for most regions in the world. Such views can now be used for cartographic purposes, especially for re-presen-tation of mountainous areas. In a modern term, let us call these kind of cartographic re-pre-sen-tations "3D mountain maps", although they must be still classified as map related represen-tations.
3D mountain maps show typical topographic features such as rock surfaces, forests and meadows, glaciers and river networks or even trekking paths, mountain cabins and further alpine infra-structures (e.g., cable cars, ski lifts, ski runs). Furthermore they could be enriched with additional thematic information about topographic aspects (e.g., height, slope steepness, orientation), geo-logy or climatic circumstances (e.g., precipitation, snow cover thickness, avalanche risks).
But how must the single topographic feature be cartographically designed in shape, style, or colour for commercial, teaching, and/or scientific purposes for an effective information transfer? Actually, there are no established cartographic principles to support the 3D map creation process as in the field of the classic two dimensional cartography.
Before we derive new principles for 3D mapping, we have to point out all eventualities and possi-bilities which affect the appearance of the represented objects of the cartographic model and also the different views on the 3D map. We should consider the so-called graphic aspects. Three types of graphic aspects can be differentiated: (1) the graphic aspects of the cartographic modelling, (2) the graphic aspects of the cartographic symbolization, and (3) the graphic aspects of the cartographic visualization. Within each graphic aspect a large number of design variables will be distinguished. Each variable influences in a unidimensional way the appearance of objects or the preferred perspective view. In a not complete overlook we want to specify and to analyse the numerous design aspects, especially for 3D mountain maps.
The developed inventory must also include the variations of the design aspect options. It will be systematically evaluated and by means of some examples of 3D mountain maps the potentially most effective values will be determined. We want to approach the best viewing settings of camera and object position as well as the best choice of the terrain and objects graphic attributes to give the map reader the most informative and memorable representation of the map content. Finally conceptual thoughts will be presented into how general cartographic principles for 3D mountain maps can be derived from such considerations about graphic aspects and design variables.