Group assignment 1.7: I’m BLUE dabadidabada#
Estimating a linear model from two very different sensors
Help we are sinking!#
There is a reason the Netherlands is called the Low Countries. Just outside Rotterdam, in the Zuidplaspolder, the ground lies almost 7 metres below sea level, and many polders around Delft are several metres below it too.
Part of the problem lies right under our feet. Much of the western Netherlands is built on soft soils such as peat, and peat has a mind of its own. It swells when it is wet and shrinks when it is dry, so the ground literally breathes up and down with the weather. Worse, when the peat sits above the groundwater table and dries out, oxygen gets in, and the peat slowly oxidizes and disappears.
To keep the land dry enough for farming, we have been pumping the water out of our polders for centuries. Lower water levels mean more dry peat, more oxidation, more subsidence… In other words, we have been pumping ourselves down.
Meet our farmer. He owns a few long, narrow peat meadows, surrounded by ditches and covered in grass (see figure below). You have probably seen parcels like his when cycling or taking the train out of Delft. He wants to know how the surface height of his land changes over time, so he has taken matters into his own hands. He installed an extensometer in one corner of his parcel to measure in situ ground displacement, and asked TU Delft to look at his land from space with InSAR satellite data (average height change of whole parcel. see yellow outline in figure).
Your Friday mission: help the farmer find out whether his parcel is sinking, and if so, how fast!
You can preview the instructions of this assignment on https://mude.citg.tudelft.nl/workbook-2026/assignments/GA1.7/README.html. After the deadline, this link will include solutions. The preview without solutions will remain available here: https://mude.citg.tudelft.nl/workbook-2026/no_solutions/assignments/GA1.7/README.html. All files of an assignment can be downloaded as .zip-file to your computer.
At 11:30, you’ll have to close laptops and receive a set of questions to be solved as a group. These questions are based on what you did in the first three hours. You can make use of notes written in the first three hours, but you are not allowed to use any other resources like AI. At 12:30, you’ll hand in your handwritten answers to the questions.
Before you can start this assignment, you should have read the theory in the book, completed the Wednesday’s workshop and the programming assignment of this week.
In this assignment you’ll make exercises on the following topics:
By Isabel Slingerland, Delft University of Technology. CC BY 4.0, more info on the Credits page of Workbook.