Re: [Tagging] The saga of landuse=reservoir vs water=reservoir

2020-12-16 Thread Joseph Guillaume
That Wikipedia page is right.
The artificial grading mostly involves creating an (earthen) dam wall
(which is often also mapped), and the purpose is generally retention of
water rather than infiltration or detention, which is why the distinction
between reservoir and basin isn't clear cut to me.

I'm having trouble thinking of it as a basin, but it does seem like this is
the intended tag. Thanks!



On Thu, 17 Dec 2020, 12:29 pm Joseph Eisenberg, 
wrote:

> What is a farm dam in this context? We don't have that term in American
> English.
>
> Is this perhaps an example of landuse=basin (or if you prefer water=basin)
> with basin=detention or basin=infiltration?
>
> https://wiki.openstreetmap.org/wiki/Tag:landuse%3Dbasin
>
> https://en.wikipedia.org/wiki/Dam_(agricultural_reservoir)
>
> -- Joseph Eisenberg
>
> On Wed, Dec 16, 2020 at 1:29 PM Joseph Guillaume <
> josephguilla...@gmail.com> wrote:
>
>> This discussion has convinced me not to use landuse=reservoir.
>>
>> It sounds like the only benefit is its historical use, whereas I've
>> personally seen benefits of the natural=water approach.
>>
>> I've mapped quite a number of farm dams as natural=water without being
>> sure what subtag to use.
>> I now think that's because there isn't an appropriate subtag. I
>> definitely don't want to tag it as a pond. While a farm dam is structurally
>> and functionally a reservoir, there are clear differences with large
>> reservoirs.
>>
>> Already now, farm dams tend to be mapped more prominently than I'd
>> expect. The dominant feature of these grazing landscapes is fencing, and
>> I'd therefore expect farm dams to appear on a similar scale to fences.
>> water=reservoir and landuse=reservoir wouldn't do that.
>>
>> One of the things I love about OSM is the ability to map incrementally,
>> which by definition results in incomplete, lower quality maps that are
>> constantly improving. If the priority was a high quality map, we'd map
>> systematically (like Missing maps, but for everything that will appear on a
>> render) and not release an area until it was done. I wouldn't be mapping.
>>
>>
>> On Thu, 17 Dec 2020, 1:26 am Tomas Straupis, 
>> wrote:
>>
>>> 2020-12-16, tr, 16:01 Mateusz Konieczny rašė:
>>> >
>>> https://wiki.openstreetmap.org/wiki/Tag:landuse%3Dreservoir#water.3Dreservoir
>>> > (just added)
>>>
>>>   Thank you. Maybe it is better to discuss here before adding to wiki?
>>>   My arguments on the points you've added:
>>>
>>>   1. Regarding benefit of having a combining level/tag natural=water.
>>> If today you would query all data with natural=water - you will get
>>> not only lakes and reservoirs grouped, but also riverbank polygons
>>> (totally different beast) and micro elements like water=pond. This
>>> could only be partly useful in the largest scale maps and only if you
>>> make very simple maps and for some reason use the same symbolisation
>>> for such different water classes. For example ponds usually have less
>>> complex and less prominent symbolisation because of their size and
>>> importance. Riverbanks would not need polygon labelling, but rather
>>> use river (central) line for label placement. Most of GIS/Cartography
>>> work goes in middle/small scales and it will be impossible to use only
>>> natural=water there, you would have to add "and water not in
>>> ('riverbank', 'pond', ...)". This erodes the benefit of "one tag" and
>>> makes it of the same complexity from coding perspective as original
>>> water scheme.
>>>
>>>   2. Very important disadvantage of water=reservoir from
>>> cartographic/gis perspective: it allows mappers to NOT differentiate
>>> between natural lakes and man made reservoirs. If first point
>>> describes how different classes are USED, this second point is about
>>> how these classes are CAPTURED.
>>>
>>>   Did I miss anything?
>>>
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Re: [Tagging] The saga of landuse=reservoir vs water=reservoir

2020-12-16 Thread Joseph Guillaume
This discussion has convinced me not to use landuse=reservoir.

It sounds like the only benefit is its historical use, whereas I've
personally seen benefits of the natural=water approach.

I've mapped quite a number of farm dams as natural=water without being sure
what subtag to use.
I now think that's because there isn't an appropriate subtag. I definitely
don't want to tag it as a pond. While a farm dam is structurally and
functionally a reservoir, there are clear differences with large reservoirs.

Already now, farm dams tend to be mapped more prominently than I'd expect.
The dominant feature of these grazing landscapes is fencing, and I'd
therefore expect farm dams to appear on a similar scale to fences.
water=reservoir and landuse=reservoir wouldn't do that.

One of the things I love about OSM is the ability to map incrementally,
which by definition results in incomplete, lower quality maps that are
constantly improving. If the priority was a high quality map, we'd map
systematically (like Missing maps, but for everything that will appear on a
render) and not release an area until it was done. I wouldn't be mapping.


On Thu, 17 Dec 2020, 1:26 am Tomas Straupis, 
wrote:

> 2020-12-16, tr, 16:01 Mateusz Konieczny rašė:
> >
> https://wiki.openstreetmap.org/wiki/Tag:landuse%3Dreservoir#water.3Dreservoir
> > (just added)
>
>   Thank you. Maybe it is better to discuss here before adding to wiki?
>   My arguments on the points you've added:
>
>   1. Regarding benefit of having a combining level/tag natural=water.
> If today you would query all data with natural=water - you will get
> not only lakes and reservoirs grouped, but also riverbank polygons
> (totally different beast) and micro elements like water=pond. This
> could only be partly useful in the largest scale maps and only if you
> make very simple maps and for some reason use the same symbolisation
> for such different water classes. For example ponds usually have less
> complex and less prominent symbolisation because of their size and
> importance. Riverbanks would not need polygon labelling, but rather
> use river (central) line for label placement. Most of GIS/Cartography
> work goes in middle/small scales and it will be impossible to use only
> natural=water there, you would have to add "and water not in
> ('riverbank', 'pond', ...)". This erodes the benefit of "one tag" and
> makes it of the same complexity from coding perspective as original
> water scheme.
>
>   2. Very important disadvantage of water=reservoir from
> cartographic/gis perspective: it allows mappers to NOT differentiate
> between natural lakes and man made reservoirs. If first point
> describes how different classes are USED, this second point is about
> how these classes are CAPTURED.
>
>   Did I miss anything?
>
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Re: [Tagging] Should the tag proposal process force voters to vote for an option?

2020-10-12 Thread Joseph Guillaume
The statement I disagree with is that "We shouldn’t be in a situation where
there is no approved way to map a mapable feature just because the
community doesn’t agree completely on how to map it."

Nobody needs approval to map anything in OSM, so approval only really
matters when there is a conflict, and I agree that conflicts are better
resolved by discussion and consensus (with confirmation by the yes/no vote)
than by voting between competing options.

If a stalled discussion means that multiple tags coexist, that's ok by me -
clearly the stakes weren't high enough in that case for compromise to
achieve coherence to be valued over the "right" tag...




On Tue, 13 Oct 2020, 11:09 am stevea,  wrote:

> Majorities can be built with reason and well-written proposals.  They
> really can.  This is where and when OSM can be at its best.
>
> Am I saying "rig an election" or "throw votes in an unethical manner"?  Of
> course not.  I'm talking about building real grass-roots support for good
> ideas that are well-stated and agreeable.  That actually happens.  And when
> it does, good for us.
>
> SteveA
>
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Re: [Tagging] "Feature Proposal - RFC - Qanat"

2020-06-22 Thread Joseph Guillaume
I suppose the reason I haven't provided an example is that historically
significant qanats are the exception in my opinion - in most cases I can't
think of a reason why it should be listed as historic other than being old.
So here's a random one:
https://www.openstreetmap.org/edit?editor=id=554179257#map=17/33.44256/50.80580



On Mon, Jun 22, 2020 at 4:24 PM Martin Koppenhoefer 
wrote:

>
>
> sent from a phone
>
> > On 22. Jun 2020, at 00:07, Joseph Guillaume 
> wrote:
> >
> > only some qanats are of historic value
>
>
> while I don’t think these must be absolutely tagged with historic=*, you
> still could show an example of a qanat that “isn’t of historic value” so
> that it becomes more convincing (or a description of one of these)
>
> Cheers Martin
>
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Re: [Tagging] "Feature Proposal - RFC - Qanat"

2020-06-21 Thread Joseph Guillaume
Hi all,

I've been in touch with the person who's mapped a lot of the
waterway=canal+man_made=canal, and they didn't have any specific rationale.

After seeing the proposal page, their preferred tagging is:

canal=qanat
elevation=-3
layer=-3
location=underground
name=Bir.1.2
status=abandoned or active
tunnel=flooded
waterway=canal

I'm not sure how to check how many other people have been mapping
man_made=qanat, but as someone who's mapped a lot of canal=qanat, I'm happy
to proceed with that as a new de facto.

I'm happy to still go to a vote if Jeisenbe would like, but I don't
personally feel comfortable mapping either man_made=qanat (too generic,
doesn't fit with waterways) or historic=aqueduct+aqueduct=qanat (visions of
Roman aqueducts don't sit well with me in this case - only some qanats are
of historic value).

Thanks for the interesting discussion,

JoeG



On Sun., 21 Jun. 2020, 4:44 am Joseph Eisenberg, 
wrote:

> > Most existing uses of man_made=qanat by the way are in combination with
> waterway=canal.
>
> Thank you for mentioning this. There are only 5 ways with man_made=qanat,
> without waterway=* - https://overpass-turbo.eu/s/Viq
>
> I will update the proposal page with this information.
>
> So there is no debate about whether or not to tag these features with
> waterway=canal.
>
> We are deciding whether or not the additional tag should be man_made=qanat
> or canal=qanat.
>
> Since waterway=canal is currently used for all kinds of irrigation canals
> and aqueducts, it makes sense to consider these irrigation features to be a
> type of canal.
>
> I have previously considered whether or not it might be sensible to create
> a whole new value of waterway=* for aqueducts and irrigation canals, but
> that does not seem to solve any particular problems: irrigation canals can
> be as narrow as 20 cm or as wide as 20 meters, as can aqueducts used for
> drinking water, so tagging usage=irrigation and width=*, while using the
> existing main tag, is probably reasonable.
>
> – Joseph Eisenberg
>
> On Sat, Jun 20, 2020 at 5:17 AM Christoph Hormann  wrote:
>
>>
>> I think this is a good idea.  Both in the sense of establishing a
>> distinct tagging for it that does not engross qanats with other types of
>> underground waterways and in the sense of using a non-English and
>> non-European term where the most descriptive and clear term comes from a
>> non-European language.  We have other cases of such tags in OSM but still
>> in a proposal process which is dominantly discussed in English this is rare
>> and kind of a litmus test for how culturally diverse tagging in OSM can be
>> and if the cultural geography of non-European regions can be mapped in the
>> classifications used locally just as we are used to doing it in Europe and
>> North America.
>>
>> Most existing uses of man_made=qanat by the way are in combination with
>> waterway=canal.
>>
>> --
>> Christoph Hormann
>> http://www.imagico.de/
>>
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Re: [Tagging] "Feature Proposal - RFC - Qanat"

2020-06-21 Thread Joseph Guillaume
Agreed, but just to be clear as it applies to this proposal, in
OpenStreetMap-land, that ship has sailed.

A canal describes "An artificial open flow waterway used to carry useful
water for transportation, waterpower, or irrigation"
https://wiki.openstreetmap.org/wiki/Tag:waterway%3Dcanal

We've de facto accepted that the tag is used with a broader meaning, which
qanats adhere to.

Cheers,

JoeG


On Mon., 22 Jun. 2020, 12:00 am ael,  wrote:

> On Sun, Jun 21, 2020 at 01:41:53PM +0100, Steve Doerr wrote:
> > For what it's worth, two points:
> >
> > 1. The Oxford English Dictionary spells this word as kanat.
> >
> > 2. It doesn't sound like anything we would refer to as a canal in
> English:
> > canals are for transportation (goods or humans) and are designed to
> > accommodate boats (even if no longer used in that way).
> >
> +1.  I have noticed this misuse of "canal" before.
>
> ael
>
>
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Re: [Tagging] "Feature Proposal - RFC - Qanat"

2020-06-20 Thread Joseph Guillaume
Hi Martin,

I may not fully understand the historic tag, but to me it is unlikely that
every qanat is of historic interest, "of sufficient importance to justify
use of this tag". In some areas, every village has three qanats. It would
be like mapping every fountain as historic.

They're often not considered of historic interest locally, let alone
nationally or internationally.

Hope this clarifies my thinking...

Cheers,

JoeG


On Sun., 21 Jun. 2020, 10:17 am Martin Koppenhoefer, 
wrote:

>
>
> sent from a phone
>
> On 21. Jun 2020, at 01:59, Paul Allen  wrote:
>
> Can there be old underground water conveying structures that people have
>> dug into the ground, that are not “historic”? Can you explain what kind of
>> situation you are thinking about?
>>
>
> The tag historic=* is not a synonym for old.  It is more nuanced than
> that.  See
> https://wiki.openstreetmap.org/wiki/Historic
>
>
>
> I am aware of the historic key and its meaning and my question stands.
> How or in which cases can a structure like this not be suitable for the
> historic key?
>
> Cheers Martin
>
>
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Re: [Tagging] "Feature Proposal - RFC - Qanat"

2020-06-20 Thread Joseph Guillaume
Hi Martin,

> for me „historic“ does not necessarily imply it is not active.

That's right - what I meant is that we should not treat every qanat as
historic just because it is old.
So we need to map the fact there is a qanat, and then someone with local
knowledge needs to map whether it is historic and/or active.

Cheers,

Joseph
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Re: [Tagging] "Feature Proposal - RFC - Qanat"

2020-06-19 Thread Joseph Guillaume
Hi Martin,

Thanks for engaging!

I don't think it's appropriate to tag them all as historic=aqueduct. That
would be like tagging canals in Europe as historic just because they were
built a long time ago. There are active efforts to maintain and restore
qanats/kariz in Afghanistan that have been destroyed or neglected due to
fighting, and there's increased attention to the fact that pumping as an
alternative lends itself to overextraction of groundwater and high energy
use.

It's also very difficult to tell whether a qanat is operational or not from
aerial imagery, so in most cases without local knowledge it's safest to map
it based on its physical features, i.e. it is a qanat, and somebody else
needs to map whether it is historical or active.
If you consider that waterway=canal should only be used for active canals,
that would be a vote in favour of the more generic man_made=qanat, but
historic=aqueduct is not appropriate.

Cheers,

Joseph





On Sat., 20 Jun. 2020, 9:36 am Martin Koppenhoefer, 
wrote:

>
>
> sent from a phone
>
> On 20. Jun 2020, at 00:59, Joseph Guillaume 
> wrote:
>
> I just wanted to emphasise that this proposal isn't really about whether
> to tag qanats - it's about whether to tag them with man_made=qanat or
> waterway=canal+canal=qanat.
>
> There's already 1000 tagged, and they're very patchy geographically. It's
> quite likely there's upwards of 100,000
>
> It would be great to be able to formally deprecate man_made=qanat before
> it becomes de facto.
>
> Hopefully we can get enough interest in this issue for the vote to be
> convincing.
>
>
>
> The issue with waterway=qanat could be that it is only applicable to those
> structures that still carry water, while many of them will not be in a
> working state, or maybe I’m misguided?
>
> I could imagine using historic=aqueduct with a subtag aqueduct=qanat for
> all of them, and add the waterway tag to distinguish working from
> nonworking?
>
> I’ve found a short article about these in Bal‘harm, a city in Sicily which
> is now better known by its current name Palermo:
> http://www.bestofsicily.com/mag/art154.htm
>
> There’s a map that suggests there are really a lot of these underground
> tunnels, but the article also states that most aren’t in a working
> condition:
>
> In fact, fresh water still flows through some of the channels. Several
> were still in use well into the sixteenth century, long after the Arabs had
> melded into the general Sicilian population
>
>
> Cheers Martin
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[Tagging] "Feature Proposal - RFC - Qanat"

2020-06-19 Thread Joseph Guillaume
Hi all,

I just wanted to emphasise that this proposal isn't really about whether to
tag qanats - it's about whether to tag them with man_made=qanat or
waterway=canal+canal=qanat.

There's already 1000 tagged, and they're very patchy geographically. It's
quite likely there's upwards of 100,000

It would be great to be able to formally deprecate man_made=qanat before it
becomes de facto.

Hopefully we can get enough interest in this issue for the vote to be
convincing.

Thanks,

JoeG
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Re: [Tagging] Feature Proposal - RFC canal=qanat

2018-09-01 Thread Joseph Guillaume
Thanks Paul and Christoph, both for your feedback and encouragement!

I've now added mention that qanats can be tagged in parallel in terms of
their historic value.
New text:
https://wiki.openstreetmap.org/w/index.php?title=Proposed_features/Qanat=1644721=1644670

I've also made a first attempt at defining qanats in general terms, and
explicitly listing names of similar features in other regions (based on the
Wikipedia article). The term "qanat" is therefore used because it is the
most commonly recognised in English.
As part of the definition of qanats, I've stated that they are always
free-flowing, not pressurized/pipe flow. I understand this is generally
true, and if there are exceptions, then a different waterway subtag might
be needed in future.
New text:
https://wiki.openstreetmap.org/w/index.php?title=Proposed_features/Qanat=1644818=1644721

Best Regards,

Joseph


On Sat, Sep 1, 2018 at 5:09 PM Joseph Guillaume 
wrote:

> Hi,
>
> I'm planning to map some qanats, underground channels for conveying
> groundwater that have vertical excavation shafts visible from the
> surface/aerial imagery (see proposal for example).
>
> This was previously discussed in 2013.
> Since then, the role of different waterway tags has been clarified, which
> indicates that waterway=canal is appropriate, combined with subtag
> canal=qanat and tunnel=flooded.
>
> Qanat shafts are still a little tricky as there are specific tags for
> mineshaft and water_well, but neither of these are really appropriate, and
> don't have a generic version.
> I'm proposing to use a generic man_made=excavation with subtag
> excavation=qanat_shaft.
>
> Here's the full proposal. Thanks to user emes, who drafted the original
> version in 2013.
>
> https://wiki.openstreetmap.org/wiki/Proposed_features/Qanat
>
> This email has two purposes: it would be great to have the formal proposal
> discussed and approved.
> But if consensus is impossible, I'll be mapping anyway, so I'm hoping for
> some feedback/alternative names before I go ahead and map 100s of them.
>
> Thanks in advance,
>
>
> Joseph
>
>
>
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[Tagging] Feature Proposal - RFC canal=qanat

2018-09-01 Thread Joseph Guillaume
Hi,

I'm planning to map some qanats, underground channels for conveying
groundwater that have vertical excavation shafts visible from the
surface/aerial imagery (see proposal for example).

This was previously discussed in 2013.
Since then, the role of different waterway tags has been clarified, which
indicates that waterway=canal is appropriate, combined with subtag
canal=qanat and tunnel=flooded.

Qanat shafts are still a little tricky as there are specific tags for
mineshaft and water_well, but neither of these are really appropriate, and
don't have a generic version.
I'm proposing to use a generic man_made=excavation with subtag
excavation=qanat_shaft.

Here's the full proposal. Thanks to user emes, who drafted the original
version in 2013.

https://wiki.openstreetmap.org/wiki/Proposed_features/Qanat

This email has two purposes: it would be great to have the formal proposal
discussed and approved.
But if consensus is impossible, I'll be mapping anyway, so I'm hoping for
some feedback/alternative names before I go ahead and map 100s of them.

Thanks in advance,


Joseph
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