When you reposition Presence on the board rather than adding new Presence, where can you measure the range from?

When you reposition Presence on the board rather than adding new Presence, where can you measure the range from?

You can measure the range from any Presence, including the one you are about to reposition.
The sequence of events for adding Presence during growth, you
  1. Choose a land to add Presence to. This must be measured from your Presence on the board at that moment.
  2. Add a Presence to that land.
Normally this is picked up from your Presence track, but you can pick it up from anywhere on the island instead if you want. The sequence is similar when a Power lets you add Presence.