Presentation: Hillshading and Draping

Hillshading and draping are tools that take a map to a whole new level. Hillshading makes the map look three dimensional and can be useful when identifying certain objects, such as river valleys and lowland areas, on a map. Draping means literally draping an image, such as a satellite image, over a terrain. Here are some examples of both tools.

This is a nice example of hillshading of the San Francisco Bay Area. If you look at a regular map of the same area, you might wonder why the bigger population centers are located in certain places. But when you see this map, you can tell how the topographic setting of the area affects where towns are located at. If you zoom close enough, you can tell that major roads are located in either valleys or on relatively flat ground.

This example map of Mile Creek Natural Area in Ithaca, New York shows a hillshaded map from an interesting angle. Digital raster graphics are combined with hillshading based on DEM. It is nice to see the effect of the contour lines, how the cartographer didn't get rid of them but chose to keep them in the map.  

Here is a nice black and white map of the Easter Island from the Australian National University. This shows how effective hillshading can be even without the use of color.

This is a geological map draped over a topographic map. Combining geological data with the elevation makes sense since you can distinguish the different geological "categories" (sorry, I have no background in geology) and where they are located in the topographical setting.

A satellite image, such as Landsat image in this map can be draped over a digital elevation model. The nice thing about this map is that the way it is displayed, it looks more three dimensional than draping the same image over a "flat" map. 

My last example is perhaps the most dramatic one of what draping can do. This is another Landsat image draped over a topographic map (from NASA's Shuttle Radar Topography Mission). It displays a part of Southern California. This map is perhaps the most life-like and illustrates the difference between elevations.