Driver.java I understood the code easily. I sometimes debate the need for comments if the methods and variables are named well. It is possible for a comment to become obsolete as the code changes. Still, I think that since the interface should be well designed, each class and method should have a description. Style of comments is different from previous files.
Consistency is the best plan.
ColorScale Mysterious formulas for 'val' variable. Not many comments, but then it is intuitively obvious to all but the most obdurate. Projection methods need to have comments to specify exactly what systems are involved. The datum, projection from and to are necessary. G2Dint.java Graph2D.java Nice commenting.