I see this on every body of water I go to and it just puzzles me. It gets windy at times and some spots of the lake are choppy but at random spots the water is smooth as glass. Does this indicate a creek channel,under water structure of what? Or is just the wind pattern doing this?

Hmmm.....can't help you there.  Not sure what that is.

Wait, wait!

 It's NESSIE!!!

Just the air mass moving - wind pattern

could be a couple things but like George said..air is the most common reason.  a depth change could also do it.

Could be a shallow area with weeds at or just beneath the surface.

I have always noticed that too and I have recognized that a lot of times it is related to a creek channel, but not always. I think it does have something to do with whats under the surface because it doesn't matter how hard the wind is blowing, it stays at the same spot on the water. BUT I can not explain it :-X Hopefully someone reads this and is knowledgable enough to explain it ;D

If it's random and moves around - it's simply the wind.  Neat little patterns, and sometimes an indicator of a gust of wind heading your way.

If the calm spot stays in one spot despite the breeze, usually it's weeds either on or just under the surface.

At least, that's how it always is in my experience.

So it's not Nessie...   :'(

It could be nessie. I volunteer you go under the water and tell us what you see!

thats what I meant with depth change.  The more shallow the water, the less choppy or disturbed its gonna look.  Weeds and other things will calm the flow of water down and make it appear "still" in an otherwise moving body, too.  

Oh MY AVID TOOK THE NEW CANOE OUT AND SWAMPED IT ALREADY

I have definitely seen that too many times but never thought to go over and check it out, the guys do seem right with the weeds answer, maybe its time to go over there and actually fish ;D

It could be nessie. I volunteer you go under the water and tell us what you see!

Ok, I did, and here's what I found....

He's real after all....

Well, I dont think you found Nessie, but it appears you found Elvis! :-/

lol and his underwater kingdom.   ;D