This data is a couple of months out of date. From the website:
These results are based on aggregated Gallup Daily tracking data from January through June, consisting of nearly 90,000 interviews nationally. Obama averaged 47% approval on a nationwide basis during this time. Each state's data is weighted so it is demographically representative of the state's population. The full data for each state can be found on page 2 of this report.
The polling puts Obama's approval rating at 47%, but in fact, Gallup's current poll puts it at 41%, with 51% disapproval. If that difference of 6% is applied across the board, Obama is underwater in all but 7 states. Of course, the national numbers aren't uniformly applicable that way, but it is still pretty likely that he's lost enough support to be under water in several more states than are showing on the map, and he's probably got fewer neutral states, as well.