# Geomedian widget¶

Note

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Geomedian composites are introduced in Session 3. Geomedians are a method of combining multiple timesteps of data into one image.

Geomedians were defined as follows:

A geomedian composite finds the median values of the bands for each pixel when considered together. This means they represent the data better than median composites.

This gives rise to a few common questions.

• What does it mean to consider the bands together?

• What might that look like?

• How does it affect the colour of each pixel in my final composite image?

To explore the answers to these questions, we can use an interactive module known as a widget. Instead of looking at one whole image, the widget focuses on a single pixel.

The geomedian widget gives three timesteps of data. You can click on the sliders to change the data for each timestep, which affects the pixel colour. In turn, this will impact the computation of the median and geomedian. As you will see, they are not always the same!

An example of what the geomedian widget looks like. To interact with the widget, download and run the geomedian widget notebook.

Follow the instructions below to download the widget notebook. It can help with understanding the following concepts:

• In which cases are the median and geomedian very similar or the same?

• In which cases are the median and geomedian very different?

• Why are geomedians more representative of the whole dataset, compared to medians?