surface=keys;values

Posted by Minh Nguyen on 2/13/2024

This week’s weeklyOSM #707 wonders aloud whether Flørauden is the most heavily tagged node in OSM. Why wonder when OSM query engines like QLever can tell us for certain?

In fact, at a mere 283 tags, this lighthouse is a featherweight compared to the top ten nodes, which are all place=country nodes weighed down by linguistic and diplomatic considerations. The most heavily tagged node of any kind has a well-known name, alt_name, official_name, and old_name in many languages.

Excluding place=country, most of the top ten nodes are place=city and place=continent nodes. But the node in sixth place caught my attention: some 250 tags on a children’s clothing store, mostly about payment methods. One is only left to wonder if a customer, paralyzed by all the options, may resort to bartering. This vandalism was removed three weeks ago, but QLever hasn’t updated to a newer Turtle extract that contains the fix.

Excluding all place=* nodes, the now payment-ambiguous clothing store, and a duplicate Sri Lanka node that was accidentally stripped of its (now fixed)… the other most heavily tagged nodes are all seamarks – lighthouses and lighted beacons.

Flørauden was 16th among seamarks until it shot up to the top a couple weeks ago. Now, with 27 different seamark:light objects tagged on it, no other seamark comes close to it in the number of seamark:light:* subkeys.

This lighthouse may not set a record, but it does illustrate why the seamark tagging scheme unusually relies on numbered subkeys instead of parallel semicolon-delimited tags. The street parking tagging scheme used to do something similar before we simplified it a couple years ago, but back then, even a notoriously well-signposted street could only muster a puny 60 tags.

Now all we need is for Null Island to become a seamark, island nation, and international security incident.