No software is able to handle them all. Humans use them to determine versions of data which are updated over time. Polygons such as these have been imported and/or curated into OSM for over a decade over many, many versions. The *ID and Shape* tags allow humans to much-more-easily determine whether data in the OSM database have changed relative to a newly-published version of data by the government GIS agency who publishes them.

Makes sense?

It is Kleene-star (regular expression syntax) mention as the last two sentences: "Sometimes tags in ALL CAPITAL LETTERS (some refer to these as "foreign keys") are left in the data when they do not logically map well to OSM tags. Where objectionable, these tags can be deleted from OSM. However, for the reasons indicated above, please leave intact (older) tags of Shape* and OBJECTID."

I hope that helps.

The other place where something similar is done is documented at osm.wiki/California/Using_CPAD_data .

The tags are mentioned at the very end of this section of the wiki page, just before the beginning of the next section (Parks).

Tagging leisure=nature_reserve is an older, still valid tag for a "less specified" area (as are these) compared to the newer tagging of boundary=protected_area (and protect_class). I am very, very familiar with this and am involved in discussions on tagging mail list as well as wiki writing / collaboration as in osm.wiki/United_States/Public_lands .

This is all horrifically complex and I'm not going to worry about the very subtle distinctions between a leisure=nature_reserve vs. a boundary=protected_area where I have to spend a lot of time determining which numeric value of protect_class is correct, as leisure=nature_reserve is "close enough."

At least in the USA, the subtle distinctions between a leisure=park (it is, in fact, a "park district" which administers these lands) and leisure=nature_reserve AND a boundary=protected_area do often blur. Part of that is American English's dialect use of the word "park" which is distinct from what OSM (and its predominantly British English leanings) means by leisure=park. A year ago, I got hung out to dry by being banned from wiki writing for a short time trying to iron out some of these semantic differences.

If you think you know better tagging on areas in my backyard, then please tag them better than I do and I'll say I appreciate you contacting me first before you do. However, I am aware of many of the semantic, political, tagging, consensus, local and OSM-global issues going on here. Maybe you are, too, in which case, I'm glad to have you as a member of the ongoing conversation.

They are not parks, in the OSM sense of leisure=park. They are "preserved areas" in the sense of leisure=nature_reserve.

I'm not really sure why these bother you so much, they are documented at osm.wiki/Santa_Cruz_County,_California#Additional_landuse_tags , where it says if these are really objectionable (I don't see them as such, perhaps you do), they can be removed. However, they are kept for the specific purpose that they distinctly aid in both tracking (with OBJECTID) and the Shape* keys (as a sort of checksum of whether the data change from upload_version to upload_version). This reasoning is documented, too.

So, I'd rather not delete them, but if you have truly good reason to do so, and you find them especially objectionable, delete them. However, offering a good reason why you might do this presented with their wiki documentation for existing seems like a good idea to offer first, though.

Some of these come from CPAD data (which have documented these apparently extraneous, but kept for good reason, for months), some come from SCCGIS data, which have been documented for a shorter time.

Is there some compelling reason (which might overtake the documented reasons for keeping them) which you find so objectionable that they should be removed?

OK, I'm trying to harmonize lcn route relations with signs I see for "local bike routes" (San Mateo County).

It's a work-in-progress and there is some noise in existing data to clean up (things tagged lcn which aren't lens as OSM defines them).

Consruction zone, basically.

Please identify the source for "Burnlingame Bicycle Routes." (relation/915719)

"misc"? That's your changeset comment? Can you be more specific? This changes rail, roads, is missing highway classifications, has highway-waterway crossing conflicts that are unresolved, not to mention disconnected highways. It changes hundreds of nodes, including many deletions as well as dozens of ways.

What was your purpose in this edit?

Yes, that seems better; correct in both cases (underlying infrastructure as route=railway and "small" trains like miniature and amusement park are route=train, not route=tram). Thanks.

Yes, while "amusement park" rail has yet to be fully fleshed out semantically (very well, very comprehensively), I'm 100% certain we don't do so with route=tram. That's a particular thing (not this). A tram might get passenger=local, but amusement park trains (like miniature trains in suburban parks, too), no, those don't get a passenger tag at all. So, that's a good place to begin to "cleave these apart," but it isn't the whole conversation.

I think we leave passenger=local off of these, for sure.

I politely disagree with the tag route=tram on BJWR. It's a route=train, it simply happens to run on miniature tracks. There are lots of these, they are trains, not trams.

I have redacted this user's changeset in addition to addressing his wrong-headed approach in changeset/81521535 's comments.

They are trails and they have every right to be mapped, especially as they are mapped with access=no. If you KNOW that trails are "illegal" then tag them as such with access=no.

However, you may NOT remove them from OSM with a heavy-handed, "let's make what truly exists invisible" attitude like you are the "trail police."

These are not being "advertised" in OSM. They are being "stated as existing" in OSM. That's all a map does: it asserts the existence of a feature. You are welcome to "richen up" any feature on the map with an additional tag that adds an additional semantic (like access=private or access=no), but you may NOT simply delete these from the map.

I am not the only person in OSM watching your activities to assure you don't continue to do this. Please abide by what OSM is: a MAP. OSM is not your mother shaking her finger at you, a fence, the police or God issuing a Commandment. So, please, don't delete, rather, tag properly.

WTF!? Who are YOU to say these "don't exist" when you only assert they are not "LegalTrailsOnly." I'm reverting this vandalism of redaction and you should be ashamed of your OSM self.

I bow deeply in obeisance in your general direction, sir.

I continue to be truly impressed with the combination of local knowledge and good OSM tagging. Please, keep up the great work!

Nice work! I recall walking this almost 40 years ago and I appreciate the update to the tagging.

It was a poorly mapped imported polygon. I have deleted it as such. Thank you for bringing this to my attention.

OK, I think I've got all the updates into OSM and downgraded the wiki from "green" (OK) PTv1 to "yellow" PTv2 (as all 4 light_rail routes are missing platforms).