Can someone please explain to me what this does?  I've read the manual but still have a hard time understanding how and why this option is implemented.

 

Thanks!

 

 

Try turning it on?

 

If it's off, overcast and you descend below 1000ft it will become sunny. Similarly in the distance hills will always appear sunny. It attempts to compensate for these faults by shading areas like these based on the cloud coverage.

 

The best effect is to run it with an offset of 3 or 4.

Thank you sir!  I had it on but wasn't exactly sure what it did.