Me again,

Contexts seem to be broken in the most recent release, if I find the issue I'll send you a pull request.

Found it:

https://github.com/echurchill/CityWorld/blob/master/src/me/daddychurchill/CityWorld/Support/PlatMap.java#L26
should be
private float naturalPlats;

This needs to be a float or else getNaturePercent returns only 0 or 1

Good spot...

I noticed that yesterday as well. I fixed it but just haven't checked it in yet. :-)