Extension Needed: Spatial Analyst
3rd Party Software: Adobe Photoshop
Swiss-style shading has been used for quite some time and originated with the great cartographers in Switzerland. It is mainly used to “normalize” the differences between high elevations and low elevations and give a slight smoother appearance to a map.
ArcMap can mimic a swiss-style effect, but in most cases you will need to bring your rasters in raster-editing software such as photoshop to fine tune your colours and shading. This brief tutorial will assume you already know the basics of creating a hillshade from your digital elevation model (DEM). Also, you will need to have the Spatial Analyst Extension enabled in ArcMap.
In ArcMap
1. Bring in a DEM and create a hillshade using the Spatial Analyst Extension. In the case below I’ve used a bright colour-scheme for my elevation ramp. You will see at the end why this colour-scheme was chosen. Incidentally, the image below is the exact colour-scheme and transparency level of the final ArcMap raster in Step 4. You’ll notice that there is too much detail in this image and it needs to be smoothed out.
2. Use the Raster Calculator in the Spatial Analyst toolbar enter the following:
DEM / 5 + Hillshade
This will create a hillshade grid from your original hillshade that will slightly lighter or darker (depending on your elevations). This is normal as it means it has smoothed out the elvations a bit and normalized the hillshade grid. Place this newly created grid below your DEM and make sure it’s colour ramp goes from Black-to-White. Set the transparency to about 55% (you can play with this number).
3. Next, open the menu in the Spatial Analyst toolbar and select Neighbourhood Statistics. Make sure that you have your original DEM selected, as well as the statistic type to mean and the neighbourhood type to circle. We usually leave the radius of the circle to a slighly higher value that the cell resolution in the original DEM. When its done calculating place this grid in between your DEM and your normalized hillshade calculated in Step 2. Set the trasparency to about 55% and make sure it’s colour ramp goes from Black-to-White.
4. Give your DEM a transparency of about 55%.
5. Export grid to a standard raster format such as PNG, TIF or BMP.
In Photoshop (Optional)
1. Create a duplicate layer of your raster and convert it (the top layer to black and white. Use a dark filter in order to bring out more shadows and hide many of the highlights. You should have 2 layers in photoshop now, the top being your newly created black-and-white image and the bottom with your original imported raster.
2. Select the top layer and select Soft Light as the draping type. From here on in there are countless things you can do. Using bright colours in the beginning tends to give more flexibility when producing the final output in photoshop.
This final output grid depicts the area around Rice Lake, Ontario. To the south, the northern edge of the Oak Ridges Moraine runs horizontally creating an interesting physiographic feature.
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