For the purposes of our discussion, a Space is defined by the image bands. Each band defines one dimension of the space. Thus if we have two spectral bands they define a two dimensional space. This space can be visualized by plotting the two spectral intensities for each pixel in a 2 dimensional x-y plot such as the figure below which is a plot of bands 1 and 2 from the Morro Bay scene.

Plot Band 1 vs Band 2 from TM scene of Morro Bay, California.

If we add another band, then we will have a 3 dimensional space. We can still visualize this and even make a 3D model (as shown below with blue data points on the tips of red pins to show location on the Band 1 - Band 2 plane) but when we add the fourth band, we must resort to arguments by analogy to the lower dimensional 2D and 3D spaces.

Plot of Bands 1, 2, and 3 of Morro Bay scene.

With the 7 spectral bands available from Thematic Mapper, a 7 dimensional space is defined by the observations.


Primary Author: Nicholas M. Short, Sr. email:

Collaborators: Code 935 NASA GSFC, GST, USAF Academy
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