I'm going to disagree with the other reviewers here and tout the effectiveness of Hemispheric Map.
A good comparison is St. Hubert's Key, a card which I run in anyone with greater than 2 who can take it. I actually think Hubert is a little too strong for a 0-level card, but it is held in check by a faction that is already laden with expensive assets.
For 3xp, you get a similar card that only costs 2 resources (MUCH better) but is conditional, so it's definitely worth a second look. I think it should be evaluated on the 2 location boost, with the 4-location boost being a nice perk to help get rid of Frozen in Fear.
I could run some numbers on how many locations in each scenario will activate its standard +1 +1 state. However, I think it's safe to say it will be at least half of the locations in the vast majority of maps. There will be exceptions (Museum, Essex, Echoes), but occasionally you'll get an exciting +2 +2 boost as a pleasant surprise (Masks, Curtain Call, Last King, City of Archives).
Ironically, this is just okay in explore-heavy Forgotten Age scenarios where you are trying to fill out the map, as you often put in a new location that is only attached to your previous one. But once you have to double-back the maps become really friendly to the map.
Overall, I've been loving this in Wendy and Solo Zoey, and I expect the same out of 3+ non- gators like Leo, Jenny, Minh (especially with Barricade[3]), Roland, Rex, and Ursula. Mystics have a variety of options they would take first like Holy Rosary, St. Hubert's Key, and Crystalline Elder Sign.