Pseudo Natural Color Composite

This image was produced using Thematic Mapper bands 1, 2, 3, and 4. Band 1 was used as blue and band 3 as red. They were contrast enhanced using a gaussian stretch with a 2.5 sigma value. Green was made from a combination of bands 2 and 4. They were added together taking only 15% of band 4 and 85% of band 3. (This process "pumps up" the green in vegetation just a bit to make it look a little more realistic (a very subjective opinion for which I take total responsibility)). The file was then converted from 24-bit true color to an 8-bit GIF file. This conversion results in very little loss of information when using landsat imagery.

False Color Composite

This image was produced using Thematic Mapper bands 3, 4, and 7. Band 4 was used as red, band 3 as green, and band 7 as blue. The image was contrast enhanced using a gaussian stretch with a 2.5 sigma value. It was then converted from a 24-bit image to an 8-bit GIF file.

Principle Component

This image was produced from the first three principle components applied to the six visible and near-infrared bands of this image. PC1 is displayed in red, PC2 in green, and PC3 in blue. The image was then contrast enhanced using a gaussian stretch with a 2.5 sigma value. The file was then converted from a 24-bit image to an 8-bit GIF file.

Digital Elevation Model

This file was produced from a 16-bit 3-Arc Second Digital Elevation Model. The image was first converted to 8-bit data (not sure of the parameters I used, but the minimum elevation of the Cuernavaca and Ciudad Altamirano 1:250,000 quad sheets was "mapped" to 0 and the maximum to 255). The image was then contrast enhanced using a gaussian stretch with a 2.5 sigma value. Since the data is b&w, it was converted to GIF and has no loss of information (other than the 16-bit to 8-bit conversion).


This file is http://www-dial.jpl.nasa.gov/~steven/mexico/notes.html
Last updated on 19 January 1996.
Comments to steven@dial.jpl.nasa.gov