The code uses a method to distribute data from one geographical level to another. The land area spatial overlap method calculates how much one level of geographical area shares boundaries with another level of geographical area.
While this method does not take into account the population density of an area in proportioning data from one area to another, it is still a highly useful and relevant method, especially when the data on population density does not exist or if one area is not a perfect subset of another.
The code uses open datasets to demonstrate an open source solution of this method. It can be used to apportion data between any geographic levels.