Matérn covariance function

The Matern covariance function is like a math equation used to describe how similar two points are in space. It describes how much the points change, or vary, in relation to their distance from each other. To understand this, it helps to think of two points on a paper. When the points on this paper are close together, then the points look similar but when the points are far away from each other, then the points look different. The Matern covariance function helps us measure how different or similar two points can look depending on how far apart they are.