Rhumb lines are not highways

A rhumb line on a portolan is a constant bearing. Sail it long enough and you will not arrive where a great-circle romantic promised. That is not a bug in the plate. That is the plate telling the truth about the instrument.

Meridian treats sources the same way.

Two coasts, one crew

When two papers disagree about a number, most tools average them, or pick the one with the nicer PDF, or hide the loser in a footnote. The plate does none of that. It draws two coasts. You can still issue a harbor later. You cannot unsee the second shore.

The first week we ran Meridian on a newsroom investigation, a junior reporter asked why the chart looked “messy.” The senior editor said: because the week was messy. That is the whole product.

What a rhumb is allowed to be

A rhumb in Meridian is a named bearing between two fragments you are willing to sail by. It has:

• a start source
• an end source
• a keeper
• a date the bearing was taken

It does not have a confidence badge pretending to be depth. Depth is a sounding. Mixing the two is how charts start to lie.

The temptation of the highway

Highways are efficient. They erase the villages they do not serve. Research tools love highways: pipelines, “canonical” records, a single timeline. Meridian will plot a rhumb if you ask. It will not pave.

If you need a road, name a harbor and put a date on it. The rest of the plate stays weather.