Learning by Doing: Sentinel-2 Application

In this exercise we want to estimate the area of water bodies in our Sentinel scene from Lahntal. As a start, load in your prepared Sentinel stack from Lahntal from the previous exercise.

“Vegetation” indices

• Get familiar with the Normalized difference vegetation index (NDVI):
  • How is the index calculated?
  • How can it help us with the identification of water bodies?
• Calculate the NDVI for the Lahntal stack.
• Plot the NDVI.
• Add the NDVI as a new layer to the existing Lahntal stack.
• Save the modified stack as a tif file.

Water bodies

• Divide your NDVI layer into two groups: water and everything else. You can use the terra::classify function.
• Now it is just a matter of counting pixels to find out the area of water bodies.

Uploading assignment to Ilias

Finalize the two assignments (i.e., Learning by Doing: Sentinel-2 Preparation and Sentinel-2 Application) and create an HTML file from your Rmd file by knitting it. Then upload both files (i.e., Rmd and html) to Ilias. See here for where exactly to place your files as well as for the file naming conventions.