Bump mapping

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Bump mapping is a process used in graphic programs to create the appearance of texture and depth to flat surfaces [1].This technique is especially useful in cartography to create a more realistic looking map surface. Bump mapping can be used to add more detail to images without increasing the number of polygons used. It can bring more life to the map. It is a method that can be applied to an entire map or just certain objects in the landscape.[2]

Application

Bump Mapping is created using the height field method, where the brightness of each pixel represents how much it sticks out from the surface [3]. A convenient way of storing bump maps is by placing them in a grey-scaled texture map. An example, and common use of bump mapping, is when making an illusion of a realistic surface of vegetation. With this technique, each bump can relate to different vegetation types to help the viewer easily distinguish differences in the land cover. For example, coned bumps can represent coniferous trees and domed bumps can represent deciduous trees. Additionally, the viewer can analyze the density, radii, and height of the bumps, which provide further information about the land cover
Vegetation shown using bump mapping on a DEM model. source: ESRI blog [4]
A close up view of the "bumps" in bump mapping.
. Cone and dome bumps resembling different vegetation.

Bump mapping can be used to show different vegetation types in a landscape, treetop mapping and creating a 3D map of buildings within a city. At the basic level, bump mapping is the same thing as texture mapping, but it is done using a different angle of illumination (typically at 300 degrees, or Northwest declination).

It is possible to obtain the Bump Map tool from the ArcGIS website to use on any type of DEM by downloading it from a link on their website [5].

See Also


Notes

  1. Rajinder Nagi, "Introducing the ArcGIS bump map tools"
  2. Nighbert, Jeffrey."A concise history of bump mapping"27 January 2010. Web. Accessed:19 September 2015.
  3. Elias, Hugo."Bump Mapping" Graphics. 8 January 2000. Web. Accessed 25 September 2012
  4. [1]
  5. https://blogs.esri.com/esri/arcgis/category/mapping/