On Wed, 23 Dec 2020 at 00:50, Brian M. Sperlongano <[email protected]> wrote:
> Great discussion, here and in the 2017 thread. Participation in the > tagging list is certainly educational. > > water=stream_pool suffers from a few problems, and its use seems far from > a settled question. (None of this is meant as criticism, as I understand > all too well the hard work involved in developing proposals and good wiki > documentation). > > In the three years since that discussion, water=stream_pool has achieved > just 425 usages. I assume that the biggest reason for this is that it's > only documented as an entry in the table for the wiki page for Key=water. > Notably absent is any mention of stream pools (or for that matter, plunge > pools) from either of the two main wiki pages for river documentation > (water=river vs waterway=riverbank). This begs the question of how > water=stream_pool should interlace with river polygons for mapping. > All the ones I've encountered the stream/river was only ever mapped as a linear way, so it's just a linear way for the stream and then an area way for the stream pool. > Stream/plunge pools are part of a river or stream (I assert this based on > Wikipedia's definition). Logically, one might think "chop up the river > polygon, and tag the stream pool portion as a stream pool". This approach > has a few problems: > > 1. If the river area is tagged with the water=river scheme, the area of > the stream pool is no longer tagged as a river (because water=stream_pool > conflicts with water=river). This is wrong because the stream/plunge pool > is indeed part of the river. You could use the waterway=riverbank scheme, > but now you're blending the two types of river tagging. Yuck. > 2. If the stream pool has a name, that portion of the river loses the name > of the river, as the polygon can only have one name= tag. The > waterway=river way of course would still carry the name, so you do still > maintain continuity. But you lose concepts like "the total surface area of > the river". > > Alternately, you could overlap the pool area over the river polygon, but > then you're double-tagging the water area which seems like poor practice, > and certainly JOSM would give you a warning for overlapping water features. > > It seems to me that river=stream_pool would have been the more sensible > tagging within the natural=water+water=river scheme, as it further > describes that portion of the river. > So for creeks would you also use river=stream_pool or have also stream=stream_pool? I guess that's fine too. I see your point, it's just I'd never really considered mapping streams/rivers with stream pools as anything other than a linear way. > The low usage and structural problems associated with stream pool tagging > suggest that this is not a ready-for-prime-time tagging scheme, and > deserves a proposal - not just a mailing list discussion - to sort out > fundamentally unanswered questions about how to tag a river with both named > and unnamed stream pools, particularly with regard to how the polygons are > divided and/or overlapped. > I don't think changing the tagging would really change the usage, but if you think there are structural issues with the tag then I'd be happy to try and comment on a proposal. > One might also argue that a stream pool should simply be mapped as a node, > and if it's too big for a node, then perhaps it's more properly tagged as a > pond or lake. Unanswered questions. > Sorry I disagree with that, because water=pond per the wiki is usually man made, and they are too small to be a lake and probably formed differently. > Stream and plunge pools are a part of rivers (per WP definition), and I > don't intend to address river tagging as part of the reservoir/lake/pond > proposal[1]. Therefore, what makes the most sense is to simply scrub > mention of pools and rivers from the proposal and leave it squarely focused > on reservoirs, lakes, and ponds. > Yeah that sounds good, a separate proposal could cover that. > > [1] https://wiki.openstreetmap.org/wiki/Proposed_features/Reservoir > > > > On Tue, Dec 22, 2020 at 12:49 AM Andrew Harvey <[email protected]> > wrote: > >> Back in 2017 this was discussed on the list >> https://lists.openstreetmap.org/pipermail/tagging/2017-March/031595.html and >> the outcome of that was I added water=stream_pool to the wiki at >> https://wiki.openstreetmap.org/wiki/Key:water#Natural_features. Is there >> any reason to change this now? I think continuing to tag these as >> natural=water + water=stream_pool is best as currently documented and in >> use. >> >> On Tue, 22 Dec 2020 at 05:13, Brian M. Sperlongano <[email protected]> >> wrote: >> >>> Discussion on the current reservoir proposal[1] (which seeks to define >>> the distinction between reservoirs, lakes, and ponds) has brought up the >>> question of stream/plunge pools[2,3], and how they fit into the lake/pond >>> definitions. >>> >>> I've come up with the following text: >>> >>> "Occasionally a river or stream will form a stream pool or plunge pool, >>> which are bodies of water that naturally occur along the course of the >>> waterway. These waterbodies may either be tagged as a lake or (usually) >>> pond if they are named or significant in size, or else they can be simply >>> conflated with the river." >>> >>> Is this distinction satisfactory? How are folks tagging these features? >>> >>> >>> [1] https://wiki.openstreetmap.org/wiki/Proposed_features/Reservoir >>> [2] https://en.wikipedia.org/wiki/Stream_pool >>> [3] https://en.wikipedia.org/wiki/Plunge_pool >>> _______________________________________________ >>> Tagging mailing list >>> [email protected] >>> https://lists.openstreetmap.org/listinfo/tagging >>> >> _______________________________________________ >> Tagging mailing list >> [email protected] >> https://lists.openstreetmap.org/listinfo/tagging >> > _______________________________________________ > Tagging mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/tagging >
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