Changing Band Combinations

Often an image contains valuable information about vegetation or land features that is not easily visible until viewed in the right way. For this reason Viewfinder has several tools for adjusting the way in which an image is viewed.

The most fundamental of these techniques is to change the arrangement of the bands of light used to make the image. In order to display an image, viewfinder assigns one color to each of up to three bands of reflected visible or non-visible light. The view we now have is called a "true color" view. In this combination, red is shown in red, green in green, and blue in blue. This makes the view appear nearly the same way as we would see it with our naked eyes. This particular image also has a non-visible near infrared band that may be useful to look at.

1. In order to change this view so we can see the near infrared band, click the Tools menu and choose arrange layers, or click the arrange layers icon icon.


2. A dialog now appears to the left of the Viewfinder, showing the current layers being used. Right click on the layer at the top of the arrange layers viewer.


3. When the menu appears choose band combinations.


4. Now the "Set Layer Combinations" dialog should appear. This is similar to the dialog we saw in the display options when first opening the ViewFinder. In order to see the near infrared band, which is band 4 in this case, we will need to change the numbers at the right of the dialog so that one of the colors displays band 4. We will try the traditional false color infrared, in which the infrared is displayed in red, the red is displayed in green, and the green is displayed in blue. To do this change the number of the band on the right in the row for the red color to 4. Likewise change the green to 3, and the blue to 2.


5. Now click OK, and close the "Arrange Layers" viewer.


6. Vegetated areas now appear in red, and non-vegetative areas in greens and blues. Here's a screenshot of an example. To learn more about band combinations see the tutorial on that topic.