Are “trap” entries a thing with phone books like “trap streets” are with maps? That’s how they get people who cross the line of fact: https://en.wikipedia.org/wiki/Trap_street

Yep! In fact, the U.S. Supreme Court decided a landmark copyright case that involved them, although tangentially. In Feist, the Court held that entries in a phone book were not, by themselves, copyrightable. The Court acknowledged that "[f]our of [the listings] were fictitious listings that Rural had inserted into its directory to detect copying," but didn't discuss the importance of those beyond that statement.

https://en.wikipedia.org/wiki/Feist_Publications,_Inc.,_v._R....

https://en.wikisource.org/wiki/Feist_Publications_v._Rural_T...

https://en.wikipedia.org/wiki/Fictitious_entry

Representing information as factual ought to result in it being treated as fact for copyright purposes, even if it's actually fictitious. In addition to opening the publisher up to liability for fraud.

I disagree. Two maps containing the same facts can present them very differently and there is plenty of scope for creative expression. So yes, the facts themselves do not fall under copyright but any non-trivial presentation arguably does.

In this case I think the MTA is still wrong though, just not for this reason.

If you take a factual data set and apply the visualization rules for "pie chart", the result will present similarly to the result of someone else applying the visualization rules for "pie chart" to the same data.

The visualization rules for "transit map" are more open to interpretation than for "pie chart", but if you look at the maps for London, Paris, Shanghai, Washington DC, Chicago, etc., they are almost self-evident:

1. Represent major stations as white circles with black outlines.

2. Represent service lines with easily distinguishable colors.

3. Constrain lines to angles divisible by 45 degrees (Paris divisible by 30 degrees).

4. Represent non-standard service with a dashed, dotted, or broken line.

5. Stations that are connected by pedestrian access are connected on the map. Minor stations, without service interchanges, may be represented by a smaller white dot or a tick mark.

Apply the rules to the facts, and the map appears. Some human tweaking may be necessary for clarity, and that is the only opportunity for copyrightable creativity to creep in.

MTA would need to assert a particular map feature that cannot be derived from applying transit map rules to the MTA transit facts. They did not.

>Fair use doesn't even come into it. Naked facts are non-copyrightable. They have no protections whatsoever. Facts are public domain.

A map isn't "naked facts", maps can certainly be copyright protected.

Yes, but a map primarily consists of facts. You can use a map for reference in creating your own map without violating copyright. Your expression of those fact (the map design) just has to be reasonably different.