lol .. I'm about 400+ hours in and did't even know this !!! I have to swipe the touch pad down though (not up) for the big map to show, also when I press & hold the touch pad the inventory doesn't show.. only the black selection screen still.
I also accidentally discovered it hahaha there is no point in the game where it teaches you to use the touchpad swipe motion to bring up the map
As for the inventory I experimented too and when i press and hold it the inventory shows up directly instead of us browsing to the Characters, Alchemy etc.