Did Paul sail or walk?

The text is more specific than it looks

Acts is unusually concrete about travel. It names the ports — Seleucia, Attalia, Neapolis, Puteoli — and it names ships, including the Alexandrian grain vessel Paul transfers to at Myra. It records winds, contrary sailing, and the decision to winter. When the narrative moves inland it says so, and when a companion goes one way while Paul goes another, as at Assos, it says that too.

So the first question is not what is plausible but what is stated. A stage Acts describes as a sailing is drawn as a sailing. A stage it describes as a walk is drawn as a walk. That covers most of the route, and it is why the map can distinguish the two at all rather than drawing one undifferentiated line.

What happens in the gaps

Acts also compresses. It will name a departure and an arrival with nothing between, sometimes across hundreds of kilometres. The map still has to show a crossing, because Paul did not teleport, but the guides say plainly that the route between those two points is reconstruction rather than something the text supplies.

Where a gap could be crossed either way, the reconstruction follows the shorter attested option and the terrain that actually permits it. Where the sources disagree with each other — as over the road behind the Galatian churches — the guides name the alternative rather than choosing in silence.

Checking routes against coastlines

A drawn route can be geographically impossible even when its endpoints are correct. Walking routes should remain on land, while sailing routes should remain at sea except when they enter or leave a port. The paths are therefore checked against real coastlines rather than accepted by appearance alone. This also keeps the visible route accountable to the mode of travel assigned in the chronology.

Some routes need intermediate waypoints to avoid cutting across a headland or sending a land journey through open water. This matters in the Aegean straits and around Fair Havens, where a simple curve between endpoints can cross an island or coastline. A port can connect a sea leg to an inland road without suggesting that the source names every turn between the recorded places.

The crossing from Troas toward Macedonia, for example, passes between islands. On a small map it can look like uninterrupted open water, but a geographically plausible route must account for Samothrace, Imbros, and the channels between them.

That check does not make a reconstructed route certain. It establishes only that the proposed mode of travel is consistent with the coastline.