Thermal Imagery and Analysis

Thermal Imagery using ETM+ Thermal and TM True Color

This week in Remote Sensing, we focused on Thermal Imagery.  Thermal imagery has all sorts of uses, from military to environmental.  I chose an environmental perspective for this lab project.

I started by creating ETMcomposite.img, a combination of 8 ETM images using ArcMap’s Composite Bands tool.  I wanted to work directly with the thermal band, so I started out with just band 6 of ETMcomposite selected.  I selected a color ramp that intuitively matches what we expect for cool to warm colors (blue to red).  By adjusting the Symbology/ Histogram breakpoints, I was able to accentuate the range of values in the overall image, really increasing the contrast between warm and cool areas.  This is really when I noticed Santay Island for the first time.  It was so cool (as in cold) in the middle of this large urban area and really not very far away physically.  It seemed to make a good ecological point that these small refuges can exist within urban areas if we take care of them.  Unfortunately, it looks like someone is already clear cutting in the middle of the island and that can be seen clearly in the thermal image.