Manual Shaded Relief of the World

Tom Patterson

Overview

This page describes a generalized shaded relief that I drew, intended for making small-scale maps of the world and continents. The relief image registers with Natural Earth vector data. It is available as a grayscale GeoTIFF (10,800 x 5,400 pixels) in the Geographic projection. The shaded relief is without the blue drainages and water bodies shown in the examples above.

Where to get it

Go to the Natural Earth website.

Why manual shaded relief?

Automated relief shading methods do not produce acceptable shaded relief at very small map scales. The problem is generalization. High-resolution elevation data when rendered yield shaded relief with excessive detail—at small scales mountain ranges look like gritty "sandpaper" textures (Figure 1, left).

Smoothing or downsampling elevation data is the usual solution to the problem of too much detail, which when rendered produces blurry, indistinct shaded relief resembling melted plastic (Figure 1, middle). Even Terrain Sculptor software, which nicely generalizes shaded reliefs at large and medium-scales, is ineffective at very small scales.

To develop an appropriately generalized world shaded relief, I turned to the manual relief shading techniques that I learned in the 1980s. (For manual relief examples, visit Shaded Relief Archive). This approach allowed me to represent complex mountain ranges as gray and white tones that captured their basic characteristics, including orientation, ruggedness, major sub ranges, and relative elevation. Given the small scale and limited space, the resulting terrain is a caricature. I also wanted the shaded relief to have a soft, clean style that could combine unobtrusively with other information on reference and thematic maps. Going back to my manual roots was the only way to create what I needed (Figure 1, right).

Figure 1. (left) Digital shaded relief rendered from 120-arc second elevation data. (middle) Digital relief rendered from smoothed elevation data. (right) Manual shaded relief.

How it was made

Using Adobe Photoshop and a Wacom tablet brought a modern dimension to this manual project (Figure 2). To draw manual shaded relief that was both stylized and accurate, I referred to a detailed digital shaded relief generated from SRTM elevation data while drawing (Figure 1, left). The digital relief was on a Photoshop layer above my drawing layer that I could toggle on and off for quick checks. Another reference layer contained Natural Earth vector drainages, coastlines, and spot elevations.

The drawing layer contained a generalized shaded relief with slightly more detail than that of Figure 1, middle. I used Natural Scene Designer Pro to create it with 1,800 percent vertical exaggeration. Drawing directly on the generalized digital relief allowed me to gauge relative elevations and provided a gray base upon which to paint lighter or darker pixels. When drawing in Photoshop, I tried not to vary the magnification level in order to keep the amount of terrain detail consistent from one region to the next.

The manual relief that I drew is not entirely manual. For example, extreme polar stretching on the Geographic projection presented drawing challenges. Consequently, Antarctica and the high arctic contain mostly digital shaded relief supplemented with manual touchups. Some large, flat areas elsewhere, such as the Amazon basin, Canadian Shield, and West Siberian Plain, also received little manual work. The digital shaded relief that appears very lightly in these areas looked acceptable.

My drawing focus correlated to terrain prominence—bigger, higher features received the most attention. I drew with a soft brush in Photoshop that I varied in size using keyboard commands (the Wacom tablet also has programmable buttons for doing this). Drawing in grayscale, I alternated between light and dark tones by toggling the foreground/background colors with another keyboard command. I applied tones lightly using multiple brush strokes with the brush opacity ranging from 10 to 50 percent. Using the pressure sensitive Wacom tablet and stylus allowed for the application of very subtle tones.

Some areas were harder to draw than others, such as mountain ranges that trend parallel to the assumed northwest light source, such as the Caucasus. In these situations, I shifted the illumination direction locally to the north or west to render a clearer depiction. Even trickier to depict were arcing mountain ranges that required switching the shadowed slopes from one side to the other, usually at natural breaks in the terrain. The mountains along the Pacific coast of North America from Alaska to British Columbia to Washington exemplify this problem. I also took into account light and shadows on adjacent terrain when locally varying the light source to maintain consistency. Another difficulty was depicting complex but relatively low terrain in an understandable manner, such as the mountains of southeast China. I had to study this area to identify trends and patterns.

Drawing shaded relief efficiently requires a relaxed, but attentive state of mind. Taking frequent breaks helps. Over thinking how to depict the terrain would slow down progress and result in poor renderings. Fortunately, working in Photoshop gives you a second or even a third chance to get it right. I redrew the Canadian Rockies three times.

Besides the mechanics of drawing, the final shaded relief is a reflection of my geographic and aesthetic preferences. Some prominent landforms hard to discern on small-scale digital relief, such as the southern Andes, received greater emphasis. I broadened and darkened the short but steep slopes that characterize these mountains. I deemphasized other areas. For example, to diminish visual noise, not all of the many mountain ranges found in the Great Basin of the US appear on the relief. Relatively low features with straight, regular sides rising above flat lowlands, such as the Ural Mountains of Russia and several mesas on the plains of northwestern Canada, appear too contrasting on digital relief. They received slight flattening adjustments.

As a final tweak to the relief art, I lightly applied Photoshop's Dry Brush and Median filters to mountain tops and other high elevation areas. This yielded crisp ridgelines that accentuated the three dimensional appearance of landforms.

Production advice

My original shaded relief drawing is darker than the released version, which has a tonal range better suited for general cartography. Nevertheless, it is likely that you will still need to adjust the tones according to the design goals of your map. The simplest way to lighten the relief is by reducing its opacity. Advanced users will want to apply curves or levels adjustments in Photoshop or a similar application. You may also want to colorize the shaded relief.

Although I drew the shaded relief to fit 1:50 million-scale Natural Earth vectors, you can print it at a range of map scales. Scales between 1:40 and 1:100 million looked fine in my tests. Just how large of a scale you can use it at depends on your tolerance of generalized relief and the purpose of your map. The final art contains more pixels than needed relative to the terrain detail, so image resolution is not an issue at modestly larger scales. At smaller scales approaching 1:200 million, the relief starts to look like a fine texture rather than a terrain depiction.

Reprojecting the shaded relief degrades image quality. For example, transforming it to the Robinson projection results in slightly blurred terrain on the map periphery. Local application of sharpening could alleviate this problem, or simply print the relief lightly so that the blurring is less noticeable.

I do not recommend using the shaded relief on polar projections. On these map projections, the terrain shadows continually change their orientation moving around the poles, potentially confusing readers.

Final thought

Drawing the shaded relief was steady, low intensity work that took 100 hours to complete. I have no desire to draw additional small-scale shaded reliefs. My hope is that a clever programmer will find an automated solution to produce similar results.

Figure 2. Cartographer selfie: drawing the shaded relief in Adobe Photoshop with a Wacom tablet and stylus.

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