stevea (2019-05-12 16:23:18+00:00): Hi Andy:  I apologize in advance for the length of this, it appears to me to be necessary.  If there is a superior venue to continue this conversation (a talk page, a mailing list...), I invite you to point the conversation there.

"Looks quite odd," how, exactly?  (That's rhetorical, you need not answer it.  I ask it that way to make the points below).

OSM's "terms" (definition) for farmland say "An area of farmland used for tillage."  That is an extremely broad definition, and technically makes even MORE area on Earth which is not so tagged in OSM likely quite deserving of this tag.  Moreover, the definition of "tillage" in my dictionary is "the preparation of land for growing crops," making OSM's definition of farmland to be:

An area of farmland used for the preparation of land for growing crops.

That is rather precisely what this is:  these lands are owned by people who prepare this land for the growing of crops, and in some cases already do (and in fact, there are landuse=orchard and landuse=vineyard areas superimposed where these are found:  I know because I have either visited them, entered them, or both).  These orchards and vineyards both have and do exist here (they come and go over the centuries, but they are both here and are allowed to be here).  In fact, any of these lands are allowed to "use the land" like this, and hence we are speaking of "land use" which in OSM is (properly, in my opinion) captured by the landuse=* tag.

(BTW for many years I have owned land here — this is literally my backyard — and both lived on it and cultivated food/fruit, herbs and flowers here.  True, my particular property is zoned residential, but as the source of many of these data are areas which are zoned "RA," meaning "Residential-Agricultural," they have both landuses.  As OSM doesn't really allow "both" (a limitation in OSM's tagging schemes which we might eventually improve to capture this semantic?) we are left to "choose one," and in fact, some of these lands do vacillate between landuse=agricultural to landuse=residential and back again.  If you truly know what's what — although, I do live here — and you wish to set this Zoning=A multipolygon to residential, of course you are welcome to do so, but it isn't RA, and I would assert that change as "less correct").

If you are "looking" (at imagery) to suggest how the land is used, this might be better dubbed "land cover."  Land cover is "what you see," contrasted with land use, which is "how the land is or can be used."  This is a frequently blurred semantic in OSM, and may be at the root of what appears to be our disagreement here (if it actually is a disagreement and not a misunderstanding).  It may be that yet another re-definition of terms in OSM is what is not-so-subtly going on, as these polygons have existed in OSM for most of its existence with no (or very little, witness your concerns here) contention, misunderstanding (as they meet our wiki definitions, both landuse=farmland and as well-describe in our local wiki) or request of their multiple authors to examine (as you do), "is this really...?"  Yes, it is as OSM defines it.  And yes, we've even gone so far as to further describe these data as "capturing zoning with landuse (is a good first step)...then replacing these with (more precise data) correctly supplement them."  Again, if you have more precise data, I invite you to supplement them.  I have, by adding the orchards and vineyards I have and that process has been underway for many years.  Finally, while I don't take credit for this (I stand shoulder-to-shoulder with many, in true OSM fashion), years ago (after my large-scale corrections of nmixter's import around v3), bestofosm.org awarded Santa Cruz a Gold Star Award, saying it had "nearly perfect landuse."  That may not be saying much, but what I heard is that we're at least on the right track.  Can improvements be made?  Of course, they have, and they continue.  It may be presumptuous to say this to you especially (I mean no disrespect), but as our landuse wiki now says today (and has for most of OSM's existence), "See Landcover for general information on tagging the physical appearance of land and Proposed features/landcover for a proposal to more clearly separate the concepts."

I don't understand why you would say that government zoning information is not useful to OSM, as zoning logically maps quite closely (if not exactly) to landuse — as OSM defines landuse.  As described in our local county wiki, "capturing zoning with landuse (is a good first step)...then replacing these with (more precise data) correctly supplement them."  I have always believed that this is exactly how OSM is intended to be "developed," and this is exactly how and why I have contributed tens of thousands of edits to do so.  Have I done something wrong over the last decade as I have?

You say "if people want the zoning info they can go to the local authority."  What OSM "wants" (apparently) are data which conform to the tags and conventions it documents in its wiki.  So that is what the (northern California) community has provided to Santa Cruz County (and other counties, like Monterey, where I was involved in a farmland data import before OSM had import guidelines, this, too, is documented in our wiki if you care to look).  They were (and are to some degree) a "first draft," intended to improve, and they have and do improve.  Again:  have I (and others) done something wrong by following our wiki documentation about landuse?  (I ask this full-well-knowing that there are many in OSM who "wish" that OSM better contain/display something resembling "more accurate land cover, given the vast visual imagery resources OSM can access," yet that is a distinctly different topic than landuse polygons which have already entered OSM.  Importantly, it doesn't make these polygons wrong.

If there actually is a trend in OSM to "convert" areas entered as landuse to something more resembling land cover, because of what can be seen in the relatively-recently-available wider use of imagery data, I welcome that conversation.  But I do not believe it fair or correct to question the entry of perfectly valid and correct data as "is this really what you mean to enter?" when it is clear (from the persistence of the data and great pains to explain how they entered and why they remain and are supplanted as they are) that they are correct.

In 2014, after I spoke at SOTM-US on how I spent between 2011 and 2014 correcting the mess of national bicycle routes as then-entered (largely by banned member NE2) into OSM as WikiProject USBRS, I experienced the DWG contacting me as Paul Norman and Serge Wroclawski had lunch with me after that 30-minute presentation, discussing "proposed" (bicycle routes, in this case) in OSM.  I was keen to listen and because I endeavor to create more light than heat, subsequently developed WikiProject methodology for "proposed" (e.g. "very high bar standard") which live on, years later.  I say this not to boast of my accomplishments, but rather to show my earnest diligence to listen to changing trends in OSM.  If there is a trend in OSM to "convert" what are perfectly valid landuse (multi)polygons now entered into what more closely hews to a land cover semantic, that's fine.  Though I ask you be forthright about that and concur with me that exactly that sort of "we're changing the rules" (again) is what is going on.  I largely find these larger-scale rule re-definitions to be disruptive to OSM, though I do "go along to get along," realizing that a certain amount of this change (or pain, depending on perspective) helps the data in the project grow towards more of what we meant to do, rather than what we actually did do.  They put erasers on the ends of pencils, as we are human and do perform mid-course corrections.

But please do not let us pretend that doing so (changing the semantics of landuse to more closely represent land cover) isn't such a mid-course correction:  it is (or would be) exactly that.  It is NOT a misunderstanding on my part, nor is it or was it mis-tagging in a way that is "probably actually not very useful to OSM" (as you say).  It is the way that OSM defined its tags at the time, as it does now and continues to do so into the foreseeable future until such time arrives that they are re-defined (as landcover or to more closely hew to that semantic) with consensus of the community.  I don't see that conversation resolving itself anytime soon, though I do continue to listen (and witness this lengthy reply) participate in it.