Alright, I can't remember when I had this first map created, but decided to go and check it out again after a few months of not playing it. Traveled around for a bit, and saw this weirdness going on. Now, does building on it mess around with anything I've already built, or is it okay to build and walk around on? *The second picture is the other side of the lake thing, right across from the area in the second picture.*
I'm assuming what you're seeing is a very old world that you decided to venture out and explore some new chunks. The terrain generation code has changed drastically and, if I remember correctly, the new generation applies to older maps when it creates brand new chunks.
All your old stuff should be fine. You're only going to run into these issues when you visit new places.
EDIT: And there should be no issue playing in the new chunks either. You'll just have to deal with the horrible transitions.
ya i think there was some glitchy chunk generation right around the 1.9-pre days, maybe 1.0. It could do things like that, and i seem to remember that it was just a single chunk at a time, or maybe a small number of them that looked out of place. you could probably find some posts about it if you look hard enough.
Although, that does seem more drastic than I remember, so the orc above may be correct as well. If Nork is correct, consider yourself lucky that it isn't more drastic.
Here's another.
All your old stuff should be fine. You're only going to run into these issues when you visit new places.
EDIT: And there should be no issue playing in the new chunks either. You'll just have to deal with the horrible transitions.
Although, that does seem more drastic than I remember, so the orc above may be correct as well. If Nork is correct, consider yourself lucky that it isn't more drastic.