This data was collected by a program we wrote as a university project, we collected Data from Flightradar24 and our own ADS-B receiver

The Data is visualized as a bitmap where the value of the pixel correspond to the relative amount of planes in the area compared to the area with the highest amount of planes using the rule of three, where [highest amount] equals a value of 255. This is our most detailed Bitmap, the data was collected over the time of a few weeks, with roughly 1.4 million tracking-datasets in our Database. We also visualized the Data in Minecraft, although the script does get a few things wrong currently

We divided the world in "quadrants" of a fixed size, about the size of 0.05° by 0.05° iirc and counted how many trackingpoints where in those quadrants