AnatomicalLandmarkCoordinates for MR T1 BIDS

An EEG colleague asked me add “AnatomicalLandmarkCoordinates” field in T1 MR json files. I read the BIDS specification and found some samples datasets. I understand that I need to supply the x, y, z coordinates for LPA, RPA, and NAS.
My question is: how do I obtain these coordinates? Do I get them by looking at the T1 images? Is there a way to automatically detect them?