This image is a derivative work of the following images: File:Population_density.png licensed with PD-USGov-NASA 2007-02-27T03:41:42Z Keenan Pepper 4320x2160
org/wikipedia/commons/thumb/1/1a/Brosen_windrose.svg/600pxBrosen_windrose.svg.png, License: GNU Free Documentation)
A compass needle aligns to the Earth’s
electromagnetic spectrum (From Wikimedia
Commons
file
“Image:
ElectromagneticSpectrum.png,” retrieved June 1, 2012)...........6
The three possible polarization states: