GLG410 3-D graphics in Matlab

One of the important tasks we have is the visualization of data that have been observed at different locations. We often want to compare the values of certain variables across our observation domain. To do this, we use contour maps and 3D views of surfaces because often that spatial distribution of a variable can be thought of as a surface, just like topography.

Basic ideas of contouring

Middleton talks about the basic rules of contouring in Chapter 8: Spatial data in his book:
Contouring can be subjective if done by hand and it almost always has some influence that comes from the method of contouring if it is done on a computer. As Middleton points out, there are three separate stages in contouring, each with its own set of algorithms:


Topogrpahy is a set of elevation versus location data. We visualize it commonly by making topographic maps. Here is one for the area of the Tempe Town Lake:

Views of the Tempe Town Lake (TTL) study area and our ongoing geophysical studies there. A) Design view of TTL illustrating its situation in the Salt River Channel just north of ASU. B) ASU Field Geophysics study area with surveyed levee topographic data and also gravity observation points overlain on pre-levee topographic map of the area. C) Topography and alluvium-bedrock interface based on gravity model illustrating the variablility of the alluvium-bedrock interface in the Pagago Narrows.

THe last figure is obviously not a contour map, but we will talk about 3D views later this week.
Look at this page for a study on contouring for one topographic dataset.

Items for Lab

Check out the Electron density demo.
Look at the contouring and 3D graphics section of the Matlab book.

Pages maintained by
Prof. Ramón Arrowsmith

Last modified November 16, 1999