Natural-colour Maps

A hyperrealistic map style

Natural-color maps are topographic maps with a particularly vivid and comprehensible symbolisation, uniting cartographic abstraction with natural appearance. We develop computer graphics methods for creating more engaging and expressive natural-colour map styles.
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A natural-color map of Schaffhausen, Switzerland.

Coloured Relief Shading

Modulating terrain colour with exposure to illumination

Maps with coloured relief shading, modulated by elevation and by exposure to illumination, present topography in a particularly vivid and descriptive manner. This digital 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, and is constructed from interactively placed colour reference points.
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Section of the school map of Schaffhausen, Switzerland

Relief Shading

Improving the perception of terrain on 2D maps

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.

We 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).

Illuminated Contour Lines

Contour lines that are easy to read

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.
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Illuminated and shadowed contour lines.

Rock and Scree Drawing

Swiss-style mountain mapping

Swiss-style rock and scree drawing for topographic maps requires considerable training and is very time intensive. The goal of this research is to automate this process. Our Scree Painter software is a specialised tool for the automatic generation of scree patterns for topographic maps. Scree Painter is used by the Federal Office of Topography swisstopo for generating scree dots for their famous map series.
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Digital scree rendering with Scree Painter (swisstopo map 1193 Tödi)

Spot Heights

Elevations of peaks, saddles and depressions on topographic maps

Spot heights and soundings explicitly indicate terrain elevation on cartographic maps. We propose a method for the automated selection of spot heights locations representing peaks, saddles and depressions. A lifespan of critical points in a continuous scale-space elevation model is employed as the main measure of the importance of features. Our results are close to reference spot heights produced manually by swisstopo cartographers.
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Spot heights locations selected by the proposed method; red: summits; blue: mountain passes. Circle size indicates importance values. Background: 1:50,000 map by swisstopo.

Hypsometric Tinting

Showing elevation with colour

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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Hypsometric tinting for atlas maps.

Terrain Generalisation for Maps

Simplifying terrain to better see it

We develop interactive methods for generalizing elevation models that allow the user to selectively remove superfluous details and enhance important terrain features.

Terrain Sculptor is an application for the generalization of terrain models for relief shading. It removes irrelevant details and accentuates important features.

Terrain Equalizer is an application for frequency filtering of terrain models. Terrain detail can be adjusted with the viewing distance.
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