As we seem to be moving in to presentational modes where 3D (mapping) is becoming ever more commonplace, enabled by software and hardware advances, it is relevant to look back at the more common pseudo 3D techniques of the past, such as relief shading, simply because this is still a very relevant presentational mode today. One of the greats of this technique was Swiss cartographer, Eduard Imhof. An example of his work, produced in 1958, is shown above. There have been several distinct techniques developed over time, but Imhof is regarded as a part of the vanguard and the benchmark by which all others are measured.
Relief shading is an established cartographic technique used to depict topography by applying a virtual illumination source to the terrain. The resultant distribution of light and shadow provides the visually attractive three-dimensional appearance of the landscape. These days, we don’t need to remove dried ink from the tips of our technical pens and/or rinse out our art brushes before we begin, but we do try and mimic this with software, in part, building upon the work of these early pioneers. In the past, cartographers made artistic adjustments to improve the legibility and realism, which most (current) software automated routines cannot, although they do a decent job by default.
There are lots of interesting articles online that look to achieve new approaches that reflect the best of both automated and manual techniques, but I will direct you to one interesting approach using Blender, an open source 3D creation tool. This two-part tutorial is by the Wandering Cartographer. This builds upon techniques achievable with lighting effects in applications such as Adobe Photoshop or Affinity Photo, layering lighting affects and blending modes, and adds more realism by introducing the way light can bounce (diffuse reflections) from surface to surface, even on faces (pixels) in shadow. In other words, it’s more than just a mathematical calculation of pixel aspect and slope. Blender‘s ability to work with DEMs is included by the excellent add-on, BlenderGIS.
If you wish to delve further in to the theoretical basis of relief shading and develop other practical techniques, four very good websites to start with are Shaded Relief, Relief Shading and the Oregon State University Cartography & Geovisualisation Group, in particular, the work of Bernie Jenny—all excellent resources. Oregon State University also has a very interesting online application, Plan Oblique Europe, enabling experimentation with parameters relevant to relief shading. Another interesting resource to explore implementation is the swisstopo interactive map tool, which is briefly discussed in the article on Swiss National Mapping. The image immediately above is an extract from the swissALTI3D Hillshade layer.
Clearly, there is a strong scientific bias as well as artistic influence upon effective relief shading, and that in itself can be off-putting, but cartography is an art and a science, so let’s flex that left brain muscle (left-right brain theory accepted, of course). Consider how you might complete the shading on image below.
It’s not been the purpose of this short article to go in to any depth about particular methodologies or techniques, but just to re-connect the relevance to modern practice and encourage further exploration. The existence of mapping frameworks, such as Mapbox, is helping us all engage with mapping as a tool to explore our physical and non-physical worlds. These are great tools, but I often find that much cartographic theory and history is forgotten and/or ignored in both their development and application. This seems to be a modern malaise—not having (or making) time to understand the past and its lessons. There are huge gains to be made in trans- and inter-discplinary practice, but not if when moving in to another discipline, say from graphic design to cartography, you do not make time to study the history and theory of the subject. I have lost count of the number of times I have read articles and listened to talks where an (ill-informed) practitioner discusses (allegedly) new advances and approaches in a mapping project, which were anything but. At best, it feels like time wasted re-inventing the wheel. Our advances should be greater than this! Something to be explored at a later date.
Postscript: I shall be adding my own experiments with relief shading here in due course, with the aim of providing a few specific techniques and examples as a follow-up to this general introduction.