Session 3 Quiz and Solution

In Session 3, you loaded Sentinel-2 data into the Sandbox using load_ard(). The first section of the exercise showed that load_ard() applies a cloud mask to each timestep in the dataset. The second part of the exercise used the same dataset to calculate and plot a cloud-free geomedian, using xr_geomedian() and rgb().


If you would like to be awarded a certificate of achievement at the end of the course, we ask that you complete the quiz. You will need to supply your email address to progress towards the certificate. After you complete the quiz, you can check if your answers were correct by pressing the View Accuracy button.

The quiz will ask you to use the notebook you developed for this session’s exercise on loading data. If you would like to confirm that your notebook works as expected, you can check it against the solution notebook provided below.


The solution notebook below does not contain the answer to the quiz. Use it to check that you implemented the exercise correctly, then use your exercise notebook to answer the quiz. Accessing the solution notebook will not affect your progression towards the certificate.

Solution notebook


We strongly encourage you to attempt the exercises on the previous two pages before downloading the solution below. This will help you learn how to use the Sandbox independently for your own analyses.

Download the solution notebook for the Session 3 exercises

To view this notebook on the Sandbox, you will need to first download it to your computer, then upload it to the Sandbox. Follow these instructions:

  1. Download the notebook by clicking the link above.

  2. On the Sandbox, open the Training folder.

  3. Click the Upload Files button as shown below.

Upload button.

  1. Select the downloaded notebook using the file browser. Click OK.

  2. The solution notebook will appear in the Training folder. Double-click to open it.