GalCiv3 Forums
Beta ver 0.82.4.0
Sometimes the planet doesn't have any easily-terraformed spots. Especially true on planets that start out high quality.
I've noticed that too. Even with unused land available it does not always allow soil enhancement.
It'd be nice if you could obsolete those projects, or if anything that can't be used were auto-removed, though.
Guess those 'perfect' planets have national park areas that are untouchable 
Check out the 6.2 patch notes that just came out, if you can't use them its grayed out 
It isn't a compete fix for this issue but its getting there lol
its not a bug apparently, if a class of a planet is high enough then it might naturally not have land that it can improve. Which makes sense considering the techs are more just to improve crappy planets not make every great planet better. Kinda an extreme example would be if you colonized the moon, and then got a tech for Ocean habitats.. wouldn't be right to say "oh i got the ocean tech i should be able to build it on this dry rock of a planet". I mean its not the same thing, but you know what i mean.
Well, this part is bugged:
Since that patch and release they broke the greying out of invalid terraforming projects.
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