3. 3D Applications

Drapes

Do you still have problems with interpreting a topographical map?

For those who still have difficulty in interpreting elevation in satellite images, a new 3D presentation called drapes can be very helpful!

Zoom Sign
Topographic map
2D map of a selected area.
Source: Petrovič, Mašera, 2006
When constructing a drape, a two-dimensional image is superimposed on a three-dimensional surface, called DEM (digital elevation model).

2D-images can be:

  • aerial photographs
  • satellite images
  • scanned maps
  • topographical maps
  • geological maps
  • orthophotos
  • property maps


In the simplest terms, the 2D-image has been draped over the ground like spreading a blanket over an uneven surface. The ground is represented by the elevation model.

Zoom Sign
Topographic map
Black-and-white orthophoto image, draped over DTM with added hill-shading.
Source: Petrovič, Mašera, 2006
Zoom Sign
Topographic map
Topographic map, draped over DTM with added hill-shading.
Source: Petrovič, Mašera, 2006

Viewing this 2D-image draped over a terrain surface helps to better understand the images and how they relate to the shape of the earth.

This mapping method is very useful especially in attaining information about remote and inaccessible areas. For example, in mountainous terrain, you can drape a satellite image over the elevation model to check access to proposed drilling sites.