Spectral features may be adjusted in two ways:

  • Interactively
  • By specifying the wavelength ranges

Interactive spectral feature definition

We may adjust the current spectral feature, selected in the list box, by dragging the color bars, corresponding to its parameters, in the spectral plot. When dragging the bar we change its position, by dragging the boundaries we may control the size.


TIP: Hold Ctrl to always drag the bar, this is useful if the bar is narrow and simple click-and-drag would result in change of the bar boundaries.

Specification of wavelength ranges

When the spectral index definition is provided in literature by wavelength ranges, we may directly specify it for each of the parameters.



Note that the actual number of spectral bands is displayed next to each parameter. In our example, each of the two parameters is computed by integrating content of two spectral bands.


In the following example, our wavelength range for parameter A does not cover any existing spectral bands in our image, this is indicated by zero bands and a warning in red. The entire image is then also displayed in red, which is the default "invalid" color.