@lzvam the MAIAC data is derived from the MODIS instruments aboard two different satellites - Terra and Aqua. The orbits pass over the poles. The third dimension of the MAIAC data represents the number of orbit overpasses - more at the poles, fewer at the equator. You can read more about it in the user guide. Page 4 is where you’ll find information about the overpasses. There are a few sites that visualize satellite orbits, like this one. Hope that helps!