Birmingham Change Detection Tutorial using MULTISPEC

1) Download the Jefferson and Shelby county LANDSAT 5 scenes from Oct 12th 1988 and Oct 20th 2008.

2) Download the MULTISPEC software from Purdue University website.

Windows Users

Mac users

3) Make sure your computer control panel settings are set to display thousands or millions of colors.
4) Open the 1988 image with the default 4-3-2 band combination for now.
5) With the 1988 image open, click File, Open Image to open the 2008 image in the same viewer window and make sure that the box is checked for "Link to active image window" in the bottom corner of the window dialogue. Then click open at this screen.
6) The exact same screen appears again in case more images are to be added. Click cancel since we have the two images we want open in the Viewer window.
7) Before proceeding, it is necessary to save this new combination as a seperate file; click Processor, then Reformat, then Change Image File Format. Click OK and then save as change.lan.
8) Open the new composite image by clicking File, Open Image and selecting change.lan. Make sure to enter 1, 7 and 1 for Red, Green and Blue channel fields respectively. Click OK in the Set Histogram Specifications window that pops up.

Result Analysis:

The resulting FCC image shows areas that have been cleared and that are likely built-up in bright green. This is because areas that are vegetated in 1988 (displayed in Red and Blue color guns) have low reflectance relative to the cleared areas in 2008 that are displayed with the Green color guns.

Areas that were built-up in both time periods are displayed in white as you have high blue reflectance in all the colors of the monitor. Areas that were clear of vegetation in 1988 had high reflectance in the visible bands and therefore equal amounts of Red and Blue show up on screen and since it is vegetated in 2008 there is relatively low reflectance in the blue band and less Green on screen and therefore this yields a magenta color. Areas that have darker colors were vegetated in both periods and therefore have low reflectance and low amounts of light in all three color guns of the computer screen.

In terms of urban expansion it is clear that most expansion is occurring along access routes heading south out of Birmingham including Highways 280 and 31, and most notably Interstate 65.