Jin wakes up in Room 23, Zoe wants his help with Dharma maps

Jin wakes up to find himself in the infamous Room 23 (where Karl was being brainwashed in season 3). He flips a switch on the wall which kills the lights and activates the video featuring "We are the cause of our own suffering" and other trippy images and phrases.

When he turns it off, he turns to find Zoe has entered the room. She tells him that Room 23 is where the Dharma Initiative performed subliminal message experiments. Jin tries to leave, but Zoe shocks him with a taser.

Once Jin is sitting on the floor, unable to properly move, Zoe pulls out an old Dharma Initiative map that identified pockets of electromagnetism on the island. She says she believes the maps are signed with the name Jin Soo-Kwon. Instead of confirming or denying it, Jin demands to see Charles Widmore. Zoe says that Widmore wants to see him too.

So what exactly is Charles Widmore planning? What is Zoe, a geophysicist, planning for use the pockets of electromagnetism on the island for?