Overview

These challenges are an addendum to the ‘Water Change Detection’ module. After your script is complete and functional, complete one or several of the challenges below. Collaborate with colleagues and your instructors. Happy Coding!

Challenge 1.

Try using a different index, such as MNDWI (Modified Normalized Difference Water Index) or a Tasseled Cap Transformation (refer to EEFA book chapter F3.1 - Section 2 Manipulating Images with Matrix Algebra), to run the change detection steps, and compare the results with those obtained from using NDWI.

Challenge 2.

Experiment with adjusting the thresholdLoss and thresholdGain values.

Challenge 3.

Use what you have learned in the Mangrove Mapping and Flood Mapping workshops to run a supervised classification on the difference layer (or layers, if you have created additional ones). Hint: To complete a supervised classification, you would need reference examples of both the stable and change classes of interest to train the classifier.

Challenge 4.

Think about how things like clouds and cloud shadows could affect the results of change detection. What do you think the two-date differencing method would pick up for images in the same year in different seasons?