Digital Terrain Rendering

Illuminated Contours

Illuminated and shadowed contour lines help map readers interpret the third dimension on a map more accurately and quickly when compared to conventional contour lines. We developed a contouring algorithm for Pyramid Shader that allows cartographers to quickly and easily create customized illuminated and shadowed contour maps. Contour line widths can be varied and colors can be alternated between illuminated and shadowed slopes. Pyramid Shader reduces the amount of time needed to create illuminated and shadowed contour lines, which were previously made by hand or through multi-step digital techniques.

Eynard, J. D. and Jenny B. (2016).
Illuminated and shadowed contour lines: Improving algorithms and evaluating effectiveness.
International Journal of Geographical Information Science.
DOI: 10.1080/13658816.2016.1144885
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Relief Shading

Existing digital shading methods ignore principles that cartographers developed in the pre-digital era. Digitally shaded relief is therefore not as successful at portraying terrain as manually produced shaded relief images.

Our goal is to transfer manual techniques for 2D relief shading maps to digital shading algorithms, and to develop new methods and algorithms for generating shaded relief images according to cartographic principles.
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Manual relief shading accentuating large landforms by local adjustment of brightness and illumination angles (by Eduard Imhof, Canton Grisons).

Marston, B. E. and Jenny, B. (2015).
Improving the representation of major landforms in analytical relief shading.
International Journal of Geographical Information Science, 29(7), p. 1144–1165.
DOI: 10.1080/13658816.2015.1009911

Leonowicz, A.M. and Jenny, B. (2010)
Automated small-scale relief shading: a new method and software application.
Geographia Technica, Special Issue, 7th ICA Mountain Cartography Workshop, Borsa, Romania, 1-5 Sep., p. 90–95.

Samsonov, T. and Jenny, B. (2015).
Small-scale and multi-scale relief mapping.
In: K. Kriz (ed.), Mountain Cartography: 16 Years ICA Commission on Mountain Cartography, Wiener Schriften zur Geographie und Kartographie, 21, University of Vienna, p. 77–86.

Räber, S., Jenny, B. and Hurni, L. (2009)
Swiss Style relief shading methodology: knowledge base for further development and application in digital cartography.
Proceedings of the 24th International Cartographic Conference ICC 2009, Santiago de Chile.

Jenny, B. (2001)
An interactive approach to analytical relief shading.
Cartographica, 38-1&2, p. 67-75.

Jenny, B. (2008)
Cartographic Relief Presentation by Eduard Imhof.
The Cartographic Journal, 45-4, p. 320 [book review].

Jenny, B., and Räber, S. (2002)
Production of shaded relief with digital tools.
Proceedings of the third ICA Mountain Cartography Workshop, Mt. Hood, Oregon.

Patterson, T., Jenny, B. (2010).
Shaded Relief Archive.

Jenny, B., Räber, S. (2002).
Relief Shading.

Colorizing Shaded Relief

Maps with coloured relief shading, modulated by elevation and by exposure to illumination, present topography in a particularly vivid and descriptive manner. Carefully modulated illumination and shading shown in continuous colour tones simulate the third dimension of topography, helping map-readers to conceive more easily the terrain’s important landforms. Since the end of the 19th century, cartographers have developed a wide variety of colour schemes.

The first part of this paper illustrates the graphical and technical developments of the past, leading to Swiss-style coloured relief shading; the second part presents a new computer-based method for colourizing grey-shaded relief inspired by classic colour schemes. The method uses a colour look-up table and a digital elevation model. The colour look-up table has colours for all combinations of initial grey values and terrain elevations. It is constructed from interactively placed colour reference points.

Jenny, B. and Hurni L. (2006)
Swiss-style colour relief shading modulated by elevation and by exposure to illumination.
The Cartographic Journal, 43-3, p. 198-207.
Henry Johns Best Paper Award by the British Cartographic Society.
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Section of a school map of Schaffhausen in Swiss-style colors produced with the developed method
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Initialization of the color look-up table from user-defined color points

Hypsometric Tinting

We developed a method for the generation of hypsometric layers based on percentile filtering. The level of details is controled by hydrological accumulation flow, and collaborated with Tom Patterson, US National Park Service, to evaluate cross-blended hypsometric tinting.
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Patterson, T. and Jenny, B. (2013)
Evaluating cross-blended hypsometric tints: A user study in the United States, Switzerland, and Germany.
Cartographic Perspectives, 75, p. 5–15.

Leonowicz, A. M., Jenny, B. and Hurni, L. (2009)
Automatic generation of hypsometric layers for small-scale maps.
Computers & Geosciences, 35, p. 2074–2083.

Patterson, T. and Jenny, B. (2011)
The development and rationale of cross-blended hypsometric tints.
Cartographic Perspectives, 69, p. 31–45.