The Argyllshire map is one of several small puzzles you'll encounter during your adventure in Hogwarts Legacy. The strategy you use to activate this puzzle might not appear immediately obvious, but once you try out a few spells, the answer will arrive, and you can unlock the hidden door hidden behind it.
How to Open the Argyllshire Map and Use the Hogwarts Legacy Button
When you install Revelio on the map, you'll receive a Field Guide page, but it will no longer do anything for the door. Instead, the only way to interact with the map, and unlock its secrets, is through the top of it. You can find it while exploring The South Wing of Hogwarts, northeast of the Clock Tower Courtyard.
How to Get to the Poidsear Coast in Hogwarts Legacy
If you want to get to this location, aim at the top of the map. Depulso is a Force spell that pushes enemies away from you. It also pushes objects away from your character, and you use this spell to unlock the door. This activates the map's center, allowing you to enter.
There are a few items you can collect in this secret room. One is a chest, and another is a small note on the desk on the right side of the room. There will also be a Moth mirror for you to complete inside this area.