The (two) episodes you are referring to are Problem Dog and Hermanos - episodes 7 and 8 of Season 4.
In the former, Hank reveals his doubts to his colleagues and reveals that a fingerprint from Gus Frings was found at Gale's apartment.
This leads them to call him in for questioning in the following episode. Gus reveals he had visited Gale to congratulate him on a scholarship. When pressed on why he has no records from his time in Chile, he reasons that he left during the dictatorship of Pinochet and record keeping was awful.
These answers appear to appease all the other lawmen present (except Hank) and Gus is released.
Following this, he begins to investigate Gus' businesses (with Walt) to try and find some sort of connection.
Now, as to your question regarding the map - I think the most likely reason is because it's far too tenuous a connection. Gus Frings is a respected business man in charge of a chain operating across the entire South West. Whilst Hank could have mentioned it, it seems unlikely his colleagues would accept it. He happens to have restaurants around the cities/districts that the drugs were found in? Well, so do a ton of other business men. What makes Frings special? The fingerprint, obviously - except Hank's colleagues have now decided that was totally innocent.
So to proceed, Hank needed something else. That, in my opinion, is why he never mentioned the map. It wouldn't have provided any sort of definitive proof.