Exercise 4.1: Calcuating indicies
Spectral Indices are central to many aspects of remote sensing. Whether you are studying vegetation or tracking fires - you will need to compute a pixel-wise ratio of 2 or more bands. The most commonly used formula for calculating an index is the
Normalized Difference between 2 bands. Earth Engine provides a helper function
to help calculate normalized indices, such as Normalized Difference Vegetation Index (NDVI). For more complex formulae, you can also use the
function to describe the calculation.
Watch this video:
The code is available in this repository under Module4/Exercise1
Your task after the exercise
The Normalized Difference Water Index (NDWI) is used for agricultural monitoring of drought and irrigation management.
The equation is: (NIR - SWIR) / (NIR + SWIR)
For Sentinel you can use NIR = Band 8 and SWIR = Band 11
- Add NDWI calculation to the script of Exercise 4.1
- Apply all indices of Exercise 4.1 + NDWI to your own study area