Terrain representation using orientation

Gene Trantham, Patrick Kennelly

Research output: Contribution to journalArticlepeer-review


A terrain data model using orientation rather than elevation permits more efficient analysis and stores its data in a multi-band raster. Representation techniques from the computer graphics industry are readily adopted with this data model. A common data model for terrain surfaces–the raster digital elevation model (DEM)–carries with it limitations by emphasizing height. Derived products such as relief shading require additional processing to determine orientation, even though they are used more frequently than those relying on elevation (e.g. hypsometric tinting). We show some of the benefits of encoding and analyzing terrain based on surface orientation, an approach that uses normal vectors stored as multi-band raster, the data storage convention in the computer graphics industry. A change in the data model and the conceptualization of the surface’s defining characteristics allows relief shading methods to run faster than conventional tools. Processing efficiencies are especially useful for more advanced shading models that may employ hundreds of relief shading calculations. In addition, an orientation-focused approach to terrain permits cartographic techniques to parallel common computer graphics methods. This project explores one such method, normal-mapping, an effect that adds texture to conventional relief shading by perturbing surface normal vectors.

Original languageEnglish (US)
Pages (from-to)479-491
Number of pages13
JournalCartography and Geographic Information Science
Issue number6
StatePublished - 2022

All Science Journal Classification (ASJC) codes

  • Geography, Planning and Development
  • Civil and Structural Engineering
  • Management of Technology and Innovation


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