The RVI is a simpler vegetation index, and is over 30 years old. The RVI is defined as: RVI = NIR/RED and simply divides the near infrared reflectance values by the visible red reflectance values. Here we will compare the two indices. Under Basic Tools, choose Band Math. Enter the following Expression:
float(b4)/float(b3)
This instructs the computer to divide the NIR (b4) channel by the Red channel (b3). The float( ) operator is necessary here since we are looking for values that are fractions and our original data are all integers.
