I live in Atlanta and I wasn't aware of any distinction between open and concealed carry. I thought that blade length was restricted to 3" or under, whether concealed or no, fixed or folding. However, in Georgia, I believe it is a FELONY to carry a blade of any kind over 2" on public transporation, or in "public areas" (hospitals, schools, churches, sports arenas, museums etc.).
I carry a 3" folder in summer (Spyderco Paramilitary today) and add a 3" fixed blade in the "winter" (such as it is). I don't use public transporation. It sucks, but it's the law. I think in the rest of the state, 4" blades are okay. But as has been mentioned above, the laws don't appear to be strictly enforced. Knife related charges seem to be brought only when the offender is engaged in additional unsavory activity, as an "add on" charge. As long as you mind your business and stay out of trouble, you should be okay. I walk past cops all the time with a clip sticking out of my pocket and have never been hassled, ever.
At any rate, a 2" bladed fixed knife should be fine anywhere in the state of Georgia, except for an airport or a courthouse.