| CI Algorithm Specification | |
The Colour Index algorithm was
developed to differentiate soils in the field - Pouget et
al.(1990).
Low valued CIs have been shown to be correlated with the presence
of a high concentration of carbonates or sulfates and higher values
to be correlated with crusted soils and sands in arid regions
(Escadfal, 1989).
In most cases the CI gives complementary information with the BI
and the NDVI. Used for diachronic analyses, they help for a better
understanding of the evolution of soil surfaces
The CI results from the following equation:
CI = (red_factor * red - green_factor * green) / (red_factor
* red + green_factor * green)
Also the processor computes an additional flags band called 'ci_flags' with the following bit coding:
| Bit Position | Description |
|---|---|
| Bit 0 | The computed value for CI is NAN or is Infinite |
| Bit 1 | The computed value for CI is less than -1 (minus one) |
| Bit 2 | The computed value for CI is greater than 1 (one) |