Exercise 3.3: Map

In this exercise, we're going to learn how to map functions to an ImageCollection using WaPOR Actual Evapotranspiration and Interception data.

The actual evapotranspiration and interception (ETIa) (dekadal, in mm/day) is the sum of the soil evaporation (E), canopy transpiration (T), and evaporation from rainfall intercepted by leaves (I). The value of each pixel represents the average daily ETIa in a given dekad.

We're going to do the following steps:

• Upload study area polygon shapefile to the Assets
• Import the WaPOR Actual Evapotranspiration and Interception ImageCollection
• Filter on date to get all dekades in a month
• Create a function for the scaling factor
• Apply the scaling function to the ImageCollection
• Calculate the average ETIa in month
• Calculate the total ETIa in a month
• Clip the result to the study area feature
• Visualise the result using a palette

Watch this video:

The code is available in this repository under Module3/Exercise3

Your task after the exercise

Modify the script of Exercise 3.3 in such a way that:

• it uses the location of your own area of interest
• it computes the monthly AETI for November 2020