It's not a hash. Each character is a one-of-32 grid square, the leftmost is the global one-of-32 grid square, each character to the right specifies a one-of-32 location within the previous parent square. 8 characters divides the globe into 32^8 = 1 out of 1.1 trillion, or about a tenth acre or a 70x70 ft square (although accuracy changes by latitude)