Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Christoph Hormann]

On Saturday 20 April 2019, Kevin Kenny wrote:
>
> I apologize for the unfortunate phrasing, and assure you that it was
> intended to be a succinct characterization of your position regarding
> indefinite boundaries, not of your personality or politics.

Thanks, i appreciate that.

When i present and argue for a position here this is not intended to 
suppress or dismiss dissenting voices, i try to convince with arguments 
which also means i emphatically present arguments that i think have 
merit.  But i also try to find convincing arguments to change my 
position.  I think it helps concentrating on the arguments and not so 
much on the people who make them.

-- 
Christoph Hormann
http://www.imagico.de/

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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Kevin Kenny]

On Fri, Apr 19, 2019 at 3:43 PM Christoph Hormann  wrote:
> Being accused of being radically intolerant and other things kind of
> limits my interest in this discussion with you.

I apologize for the unfortunate phrasing, and assure you that it was
intended to be a succinct characterization of your position regarding
indefinite boundaries, not of your personality or politics. I myself
am radically intolerant, for instance, of completely fictitious
features in OSM added by people who believe that it will confer some
advantage in an online game. Not of the people - they need to be
gently guided into more responsible pursuits, nor of the game, about
which I know little other than that my daughter plays from time to
time, but of the mess that is left behind - the proper approach there
is indeed not to tolerate it, but to take the literally radical step
of uprooting it.

All that I offer in my defense was that the phrase appeared in a
dialogue in which phrases like 'cultural imperialism' were already
being bandied about, and so the standards of discourse were already
relatively lax.

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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Christoph Hormann]

On Friday 19 April 2019, Kevin Kenny wrote:
> > It is interesting that the idea that large size abstract concepts
> > projected onto arbitrarily delineated parts of the physical
> > geography by cultural convention like bays, peninsulas, linear
> > rivers and plateaus might not be suitable for being recorded in OSM
> > is by several people in this discussion reinterpreted as - and i am
> > only slightly exaggerating here - that mappers may only record
> > things after they have personally touched every centimeter of them.
>
> The fact that as many people 'reinterpreted' your words suggests that
> it might behoove you to review them.

I do that all the time, usually also preemptively, which is why i tend 
to formulate carefully to avoid misunderstandings.  In this case i 
think i have explained my idea clearly enough to Graeme - if not he is 
of course welcome to ask for further clarification.

Being accused of being radically intolerant and other things kind of 
limits my interest in this discussion with you.  I can see why you 
reject the idea there are things that should not be part of the OSM 
database despite them being part of the geographic reality as you see 
it and i also see why you have a general preference for representing 
these things in the OSM database with polygons.  But i also see very 
good reasons why you should change your position on that - some of 
which i explained in my comments here.  I could be wrong about this of 
course.

-- 
Christoph Hormann
http://www.imagico.de/

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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Kevin Kenny]

On Fri, Apr 19, 2019 at 6:28 AM Christoph Hormann  wrote:
> It is interesting that the idea that large size abstract concepts
> projected onto arbitrarily delineated parts of the physical geography
> by cultural convention like bays, peninsulas, linear rivers and
> plateaus might not be suitable for being recorded in OSM is by several
> people in this discussion reinterpreted as - and i am only slightly
> exaggerating here - that mappers may only record things after they have
> personally touched every centimeter of them.

The fact that as many people 'reinterpreted' your words suggests that
it might behoove you to review them.

In any case, we're in agreement that the Bay of Biscay, the Drake
Passage or the Bight of Benin are quite problematic for arbitrariness.
Something near half of their boundaries are arbitrary - worse in the
case of the Drake Passage. There is some sort of problem involving
these objects that would merit investigation. They are not what I'm
talking about here.

I've at least heard you as arguing that no OSM object ought to have an
arbitrary boundary, anywhere on its perimeter.  That rules out almost
all waterways, most of which are connected to other waterways by
rivers or straits. Of course, it rules out peninsulæ and isthmuses.

I know we've had a disagreement before about the Hudson River, where
your interpretation of 'coastline' unambiguously denies the river's
existence for the lower 200+ km of its reach - all because the
boundary between riparian, estuarine and marine environments cannot be
established without drawing an arbitrary line, and the first
unambiguous physical boundary for where it is unquestionably a 'river'
is the Federal Dam in Troy, New York.  If locals are consulted, they
will place the river's mouth at the Battery on the southern tip of
Manhattan Island - but somehow, in the quest to destroy all potential
ambiguity, deferring to the locals in this instance is cultural
imperialism. We've been through several proposals for defining the
riparian/estuarine/marine border, for river mouths and complex
coastlines. All have failed on a great many objects in the perception
of the local mappers. Despte your radical intolerance for ambiguity, I
think we do have a broad consensus among the other mappers that the
locals are virtually always right.

I return to the example of the Red Sea. I know of no culture that
denies that it is a single named entity.  It has hundreds of km of
coastline, and its borders (except for the mouths of streams, which
are rare in the desert surrounding it) are well defined, with two very
small arbitrary borders: the entrance to the Suëz canal and the narrow
straits on either side of the island of Perim (Ar: Barim: بريم‎).  It
is possible for reasonable people to disagree, perhaps, about whether
the villiage of Faghal (فغال - I may be mistransliterating) is on the
Red Sea or the Persian Gulf, but for hundreds of km, there is no
ambiguity: nobody would disagree that Port Sudan (بور سودان) is a port
on the Red Sea.  Mapping the Red Sea as a single point loses that
topologic and shape information. It is throwing the baby away with the
bath water. Whether Faghal is or is not on the Red Sea is a question
that I am happy to leave to any mapper in Faghal who is willing to
offer a local judgment! To the extent to which such judgments trigger
political or cultural conflicts, there will never be a good solution
in OSM. If the locals are currently fighting a war over a boundary,
OSM cannot resolve the question of where the boundary lies.

The Black Sea, of course, offers a similar problem in construction.
Tiny arbitrary lines have to be drawn across the Bosphorus, the Strait
of Kerch, and some river mouths.

I do not accept the idea that the Red Sea is an abstract concept
without a relevant geographic feature bound to it. I do not accept
that "Port Sudan is on the Red Sea, and Odessa is on the Black Sea"
are not verifiable facts. The fact that the seas are joined to narrow
straits across which arbitrary lines must be drawn does not negate the
existence of the Red Sea, or the Black Sea.

It is not just waterbodies and peninsulæ, but even administrative
boundaries have this issue. I live in a state where portions of some
county lines are indefinite - they are in uninhabited wilderness and
have never been surveyed. Nevertheless, the definite portions of the
lines are necessary, as is a consistent topology. For a point in an
inhabited area, where the lines are established, one needs to be able
to compute with certainty, "is this point in Franklin or Essex
County?" Yes, if you choose a point in the uninhabited wilderness, the
answer might be, "I don't know" or might be wrong. But nobody cares
about the answer for an arbitrary point in uninhabited wilderness. A
wrong answer is perfectly acceptable. (It would not be acceptable to
say that the point is in Suffolk County, hundreds of km away, clearly.
But to answer which of two neighbouring counties owns it is 

Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Michael Reichert]

Hi,

Am 18/04/2019 um 18.52 schrieb Christoph Hormann:
> On Thursday 18 April 2019, Kevin Kenny wrote:
>> Please avoid the term "label painting." What you call "label
>> painting" is the entirely reasonable desire to have recognized, named
>> objects appear on the map with their names.
> 
> I distinguish between names and labels.  Labels are graphical 
> representations of names or other strings in map renderings.  The OSM 
> database should not contain labels, it should contain names.
> 
> This:
> 
> https://www.openstreetmap.org/relation/9359806
> 
> is not a named representation of a verifiable element of the geography, 
> it is a labeling geometry.  Creating such is not mapping, it is label 
> drawing or label painting.  It is neither meant nor suited to do 
> anything other than performing a relatively simple label placement.
> 
> Note by speaking of "label painting" i do not intend to assign one sided 
> blame to mappers for doing so.  In most cases this is as much the fault 
> of map designers encouraging this as it is of mappers to respond to 
> this incentive.

+1

Best regards

Michael

-- 
Per E-Mail kommuniziere ich bevorzugt GPG-verschlüsselt. (Mailinglisten
ausgenommen)
I prefer GPG encryption of emails. (does not apply on mailing lists)



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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Christoph Hormann]

On Friday 19 April 2019, Graeme Fitzpatrick wrote:
> > But as already hinted i am not sure if the Drake Passage is
> > something i would consider mappable in OSM based on local
> > knowledge.
>
> But, without wishing to sound facetious, how do we then have
> coastlines for Eurasia, Greenland & Antarctica mapped?
>
> *Nobody* has "local knowledge" of the full coastline of any of them,
> & for Greenland & Antarctica, what is mapped - the ice cap, which is
> constantly moving, or the deep underlying rock? Should we erase them
> off the map as they're not "verifiable"?

It is interesting that the idea that large size abstract concepts 
projected onto arbitrarily delineated parts of the physical geography  
by cultural convention like bays, peninsulas, linear rivers and 
plateaus might not be suitable for being recorded in OSM is by several 
people in this discussion reinterpreted as - and i am only slightly 
exaggerating here - that mappers may only record things after they have 
personally touched every centimeter of them.

That does not make much sense of course.  Physical presence near a 
certain geographic setting can help you immensely to acquire local 
knowledge of it but it is neither a guarantee for doing so nor a 
prerequisite for mapping things.  And as said in the past verifiability 
based on local knowledge does not require everything in the database to 
be independently verified by several mappers with local knowledge.  It 
just requires the possibility to do so.

When mapping the coastline of Greenland or the Antarctic you have 
several independently recorded image sources available (not what you 
find in Bing & co. though - that is all the same 20 year old stuff) 
where you can localize the coastline on and there are also quite a few 
people mapping in OSM who have visited these areas.  This is definitely 
not a problem of lack of local verifiability.  In cases of doubt (which 
there might be, in particular if sea ice is present on images) we can 
look together at the images to resolve the situation or we can consult 
people with local knowledge.

-- 
Christoph Hormann
http://www.imagico.de/

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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Mateusz Konieczny]

Apr 19, 2019, 1:59 AM by graemefi...@gmail.com:

>
>
> On Fri, 19 Apr 2019 at 07:26, Christoph Hormann <> o...@imagico.de 
> > > wrote:
>
>> On Thursday 18 April 2019, Kevin Kenny wrote:
>>  > > And how do you verifiably determine if two things are part of the
>>  > > same physical object? 
>>
>>  But as already hinted i am not sure if the Drake Passage is something i 
>>  would consider mappable in OSM based on local knowledge. 
>>
>
> But, without wishing to sound facetious, how do we then have coastlines for 
> Eurasia, Greenland & Antarctica mapped?
>
> Nobody>  has "local knowledge" of the full coastline of any of them, & for 
> Greenland & Antarctica, what is mapped - the ice cap, which is constantly 
> moving, or the deep underlying rock? Should we erase them off the map as 
> they're not "verifiable"?
>
Coastline can be mapped in fragments and every single part of coastline is 
locally verifiable.

It is not true for objects like oceans, mountain ranges, continents etc.

You can go to a beach and check whatever land is on one side and water on other 
and check
shape of a coastline.

It is impossible to do it with border between oceans.
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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Graeme Fitzpatrick]

On Fri, 19 Apr 2019 at 07:26, Christoph Hormann  wrote:

> On Thursday 18 April 2019, Kevin Kenny wrote:
> > > And how do you verifiably determine if two things are part of the
> > > same physical object?
>
> But as already hinted i am not sure if the Drake Passage is something i
> would consider mappable in OSM based on local knowledge.
>

But, without wishing to sound facetious, how do we then have coastlines for
Eurasia, Greenland & Antarctica mapped?

*Nobody* has "local knowledge" of the full coastline of any of them, & for
Greenland & Antarctica, what is mapped - the ice cap, which is constantly
moving, or the deep underlying rock? Should we erase them off the map as
they're not "verifiable"?

Thanks

Graeme
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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Christoph Hormann]

On Thursday 18 April 2019, Kevin Kenny wrote:
> > And how do you verifiably determine if two things are part of the
> > same physical object?  For example: [examples snipped]
>
> I'm all for a rule of, 'if in doubt, split,' possibly paired with
> creating a new relation to carry the grouping.  You seem to favour a
> rule of 'never join,' which is perverse for the common case where
> there is broad consensus about object identity.

As mentioned in terms of physical geography the only cases where there 
is broad consensus on the identity of large size features and if and 
how to represent them in the OSM are lakes and islands.  For most other 
things mapped mostly with polygons, in particular stuff rendered 
typically with a color fill, it is widely accepted that polygons are 
split and most mappers prefer small and easy to handle divisions.  Many 
mapping conventions we have even require this - for example if part of 
a forest is needleleaved, part is mixed, you have to split it to 
represent this fact in the data.

Even for lakes we have cases where this applies by the way.  Lake 
Balkhash is a lake of which part is freshwater and part is saltwater 
which is mapped separately despite the name applying to both parts:

https://www.openstreetmap.org/relation/35904
https://www.openstreetmap.org/relation/3367363

If you consider this a bad idea that's fine.  But it stems from the 
fundamental idea of mapping local geographic knowledge.  For locals at 
the eastern part this is locally Lake Balkhash and it is saltwater.  
For locals at the western part this is also Lake Balkhash and it is 
freshwater.  And that is perfectly fine and nothing should require 
these mappers to settle for a uniform but locally inaccurate 
representation of the geography.

> > I distinguish between names and labels.  Labels are graphical
> > representations of names or other strings in map renderings.  The
> > OSM database should not contain labels, it should contain names.
>
> On this, we agree. To what object should the name, 'Jamaica Bay' be
> assigned? How can such an object be constructed? The locals can
> clearly define its extents, except for very small indefinite
> boundaries over narrow entrances and exits. What should be done to
> give that object, which unquestionably is observable in the field as
> an entity distinct from the ocean, existence in OSM?

I respect your desire to find a consensus for how to represent this 
particular feature but this doesn't really have much to do with the 
subject here, that is to what extent we can and should map large size 
concepts in OSM.  Jamaica Bay is beyond any doubt small enough to be 
mapped under the rule of thumb i proposed so discussing this is IMO not 
a matter of if it should be mapped but only potentially what is the 
best way to map it recording all verifiable knowledge of it in an 
efficient way.  I would like to separate that discussion from the 
subject here.  IIRC in our previous discussion on this i made a 
principal point that creating a polygon is unnecessary even here but i 
don't think i really objected to using one.

> We have that at one extreme, a case where almost all the boundaries
> are indefinite.  Nevertheless, the Drake Passage has some sort of
> existence.

Yes.  Leaving aside for the moment the question if something like the 
Drake Passage should be represented in OSM - the Drake Passage is a 
great example for a strait where no geometric information is required 
beyond a node to fully represent the feature in its spatial 
characteristics.

The Drake Passage is the passage/strait between Cape Horn (the southern 
end of South America) and the Antarctic.  As a prototype of a strait 
between two convex land masses it has no length but only a width.  It 
is perfectly documented with a node placed half way from Cape Horn to 
the closest point in the Antarctic (on the South Shetland Islands).

But as already hinted i am not sure if the Drake Passage is something i 
would consider mappable in OSM based on local knowledge.  Of course as 
long as it was mapped with a simple node it did not really bother 
anyone - you could as a mapper or data user simply ignore it.

-- 
Christoph Hormann
http://www.imagico.de/

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[Tagging] Stop the large feature madness

[Michael Patrick]

 > The idea that every object, even among those that can be easily mapped
in a day, has a single True Name, is simply an incorrect assumption
around here.

A few months ago, I went to a mixer hosted by a new online real estate
startup, and the attendees were an interesting mix of neighborhood low
income housing activists, property managers, and city officials.

I was noticed some of their listing had notations that the property was in
'neighborhood Y', when actually it was, IMHO, in 'neighborhood X' because I
had lived their, and according to the city 'association' map, it was in
'neighborhood Z'. Now, 'neighborhood X' had historically been of somewhat
ill repute ( like newspaper crime and environmental reporting ), and 'X'
had some fairly definite walking, connectivity, commerce ( The' X Market'
), and boundary elements.

The city people admitted that their map was made quickly and they had
basically used Census boundaries and never checked with anyone, and nobody
ever complained, and said they were really open to changing it, that it was
only a temporary place holder. The activist noted their neighborhood had
been divided and assigned to two others, essentially erasing their
semi-official status. The property management people were looking really
uncomfortable, and as I continued scanning the listings, found that they
had invented a few new 'plausible' neighborhoods 'neighborhood "T Street'
and 'neighborhood S Street' and assigned some listings to the higher income
'neighborhood Y'. When I pressed them, they said it was because they could
charge higher lease rates, and based on client feedback, nobody wanted to
live in 'neighborhood X' when a Google Search was done.

I gave the start-up founder my copy of 'Seattle Geographies' in sympathy,
advised him to read it, and left before the serious blood letting began:
http://www.aag.org/cs/aag_bookstore/other_publications/seattle_geographies

There's been a long term feud going about the local 'International
District':
https://www.seattletimes.com/seattle-news/name-feud-clouds-opening-of-library/

+1 on "There is no single True Name"

Kenny, that was an absolutely wonderful post on New England geographies.

Michael Patrick
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Re: [Tagging] Stop the large feature madness

[marc marc]

Le 18.04.19 à 20:29, Christoph Hormann a écrit :
> you verify the information on the ground and if there is still 
> disagreement it is by definition something that is not verifiable
> (because several mappers evaluating the situation independently 
> do not consistently come to the same results). 

with your argument, if I disagree with the boundaries of a country,
it will be necessary to remove all the nodes of the boundary except 
historical landmarks, border crossings and where there would be a sign
because everything else is not "on ground verifiable" ?
welcome to OpenPurgedMap :-)

with a municipality I am working on, in one year I only found 2 
historical landmarks, whereas there are 404 nodes in osm. I hope
that nobody will contest the verifiable of the border, otherwise
a municipality boundary with 2 nodes will be ridiculous.
imho this demonstrate by the absurdity that the argument "in case
of disagreement, only on-ground verifiable information is kept"
does not work. it's so extreme that it's inapplicable.
please come back to reality or fork a OpenGroundOnlyMap
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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Paul Allen]

On Thu, 18 Apr 2019 at 21:00, Kevin Kenny  wrote:

>
> The controversy lies not in the choice of tag but rather in the
> presence of long indefinite boundaries.
>

I thought part of the controversy was the very large polygons involved.
You can map a
strait as a way or a node.

Some may think of it as label painting, but that is a definite geographical
feature.  A passage
which is generally preferred to other routes through narrower straits even
though the weather
is a little rougher.

I'm with you on this one.  If the rules we work to insist that we cannot
map features such as
this so that people can see them on OSM then the rules are wrong.

-- 
Paul
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Re: [Tagging] Stop the large feature madness

[Kevin Kenny]

On Thu, Apr 18, 2019 at 2:30 PM Christoph Hormann  wrote:
> No, the concept of verifiability defines a clear path for resolving
> disagreement - you verify the information on the ground and if there is
> still disagreement it is by definition something that is not verifiable
> (because several mappers evaluating the situation independently do not
> consistently come to the same results).

In the specific case of names, we've invented name:language and
alt_name and old_name and name_1, name_2, etc. to deal with the cases
of, 'everyone agrees that there's a pond/mountain/building/whatever
here, but not all the locals call it by the same name.' The name may
be verifiable in that if you have a sufficiently large sample of
locals, you'll hear it, or if you ask, you may get the answer, "yes,
that's what some people call it."

I do recognize that you tend toward the 'strict verifiability' camp,
and that I've somewhat caricatured it by saying 'if a stranger dropped
into a location can verify everything about it by direct observation
without consulting the locals or outside sources.' That strict a
definition excludes a good many names, at least in the rural US, which
isn't big on hanging a sign on every named feature.

The idea that every object, even among those that can be easily mapped
in a day, has a single True Name, is simply an incorrect assumption
around here.

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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Kevin Kenny]

On Thu, Apr 18, 2019 at 3:49 PM Paul Allen  wrote:
> How about natural=strait?  For very large values of "strait."  Or, if you 
> don't like the idea
> of large values of strait, rewrite the wiki page changing
>
> A strait is a narrow area of water surrounded by land on two sides and by 
> water on two other sides forming a connection between those bodies of water.
> to
> A strait is a channel of water surrounded by land on two sides and by water 
> on two other sides forming a connection between those bodies of water.
>
> Because the point of a strait is not that it is narrow in absolute terms but 
> that it is narrower than
> the bodies of water it connects.  OTOH, it is a very large value of "strait."

The controversy lies not in the choice of tag but rather in the
presence of long indefinite boundaries.

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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Paul Allen]

On Thu, 18 Apr 2019 at 20:27, Kevin Kenny  wrote:

>
> We have that at one extreme, a case where almost all the boundaries
> are indefinite.  Nevertheless, the Drake Passage has some sort of
> existence. If a map user reads the sentence, 'The _Nancie Belle,_
> having survived the perilous journey through the Drake Passage, turned
> to the north and made for Buenos Aires,' then that user might well
> ask, "Where's the Drake Passage?". Should OpenStreetMap contain the
> information needed to answer that question, perhaps through a
> Nominatim query?  If so, in what form should that information be
> represented?  Ought that information be in such a form that a map of
> the Southern Ocean can render it competently, or is that rendering not
> a job for OSM?
>

How about natural=strait?  For very large values of "strait."  Or, if you
don't like the idea
of large values of strait, rewrite the wiki page changing

A strait is a narrow area of water surrounded by land on two sides and by
water on two other sides forming a connection between those bodies of
water.
to
A strait is a channel of water surrounded by land on two sides and by water
on two other sides forming a connection between those bodies of water.

Because the point of a strait is not that it is narrow in absolute terms
but that it is narrower than
the bodies of water it connects.  OTOH, it is a very large value of
"strait."

-- 
Paul
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Re: [Tagging] Stop the large feature madness

[Michael Patrick]

... INRE: http://bit.ly/2IGkgoj

> Nobody proposed ban on mapping things far away from your place of
residence.

> That's an amazing image, thanks Michael.

Hmmm ... it's not a really a bona fide 'map',
per se,it's really just a silly snarky sarcastic
cartoon based on narrow assumptions and
a highly suspect data model - inspired by
my personal knee jerk reaction to other
community members perfectly justifiable
philosophies of what OSM 'is'.

> I take it that's the home location of all OSM contributors?

Ummm ... No, I stated a hypothetical 'What
if' scenario: " If everyone on Earth joined OSM ...",
so the 'locations' are based on the entire
global population derived from:*"*Center for
International Earth Science Information Network
- CIESIN - Columbia University. 2016. Gridded
Population of the World, Version 4 (GPWv4):
Population Density. Palisades, NY: NASA
Socioeconomic Data and Applications Center
(SEDAC). http://dx.doi.org/10.7927/H4NP22DQ
that I use frequently.

I also do time space / mapping, so for the second
'constraint', '...and limited their mapping to their
own local knowledge', from my knowledge of
Torsten Hägerstrand's ( et. al. ) framework of
time / space trajectories of individual humans
in the environment, I made S.W.A.G. to get a
'home range' of our set of global mappers.
( https://www.spektrum.de/lexika/images/geogr/fff59_w.jpg ).
I then made a mad leap to a conclusion that this
'range' was approximately the same as the grid
size. ( maybe not so mad, there is a vast literature
around this: http://meipokwan.org/Gallery/STPaths.htm
... and some folks have even extended the model into
'virtual spaces' like WoW ).

I then sampled some area like the middle of the
Sahara, Siberia, Yukon Territory to get a lower
bound ( nobody lives here ) and did a blunt
overly simplified binary classification, and used
this as a mask to punch out the OSM world map.

The projection used is psychological, not
geographical ( https://en.wikipedia.org/wiki/Psychological_projection ).

> ... also a bit surprised that Australia & NZ have
dropped back into the Ocean - I thought there
were a few more of us than that? ..

See http://worldpopulationreview.com/countries/countries-by-density/
Australia is 225 ( out of 230 ) and NZ is 198.
It's actually even more dramatic than this,
the Australian Census even has a special
distinction for remote areas. It's also an
artifact of the population dataset in
relation to the resolution of the final
graphic. If you are feeling left out, I
can adjust that single pixel value.

> (cc'ed to AU list for interest's sake :-))

Please tell them this wasn't serious, I
don't want to get kicked out of the union.

> Nice and funny illustration of OSM problems
with global and remote natural areas. How did
you create it?

Thank you, and see above. A little used
GIS tool called InkScape ( perfectly
good for doing raster analysis, most
'art' tools ( like 'burning', etc. ) are
equivalent to some GIS raster math.

> Nobody proposed ban on mapping
> things far away from your place of residence.

Embedded in Hägerstrand( et. al. ) is that
notion of what is 'near' and 'far' for an
individual and their experiences. I can
look out an airplane window and make
a pretty good guess what state I'm over
by the road network ( http://www.legallandconverter.com/images/RSS1.jpg ),
but while my neighbor gets lost walking
to the store - but he can tell you every
landmark in his online games. We're all
different.

> That would probably only add to this picture
some spots (remote settlements and touristic
attractions) and thin lines (along routes).And
probably only spots, if single day would be the limit.

You hit the nail on the head. Humans have
just so much attentional bandwidth.

> OSM started as a very local enterprise, but
the world is much wider, so we should rethink
how to deal with them, because the world is
not gonna shrink...

https://www.newscientist.com/article/dn27875-earths-shrinking-crust-could-leave-us-living-on-a-water-world/
... but you do have a point, there. :-)

Michael Patrick
Geographer
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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Kevin Kenny]

On Thu, Apr 18, 2019 at 12:53 PM Christoph Hormann  wrote:

> How should they determine that based on local knowledge?  What if there
> is disagreement?  Is
> https://www.openstreetmap.org/way/83015625
> the same river as
> https://www.openstreetmap.org/way/4769426
> or
> https://www.openstreetmap.org/way/174752117
> or
> https://www.openstreetmap.org/way/234008385

I can't comment, not being familiar with the local situation.
Certainly, there is a well-known situation in the US, the 'Ohio', the
'Allegheny' and the 'Monongahela' rivers are considered by the locals
to be three distinct objects, with the first formed by the confluence
of the other two. The Ohio begins in Pittsburgh. Neither of its two
tributaries is the Ohio.  If your example is similar, it's appropriate
to separate them in the database.  I presume that 'Aar', 'Vorderrhein'
and 'Hinterrhein' are conceptually similar - sections, tributaries or
distributaries of the Rhine, with their own distinct identities.

> What if the local mappers do not speak the same language?  Do those who
> speak English automatically get to overrule those who don't?

We've dealt with the issue of names in different languages before, and
it's not necessarily a problem. A few tens of km north of me, nobody
would argue that 'Lac du Saint-Sacrement' and 'Lake George' are
distinct lakes. Whether a mapper speaks English or French, they'd
recognize the lake itself as being the same object, with different
names in two languages. 'Fleuve Saint-Laurent' and the 'Saint Lawrence
River' are the same river, and the speakers of both languages agree on
its identity, even if not its name. It's when the different cultures
or language groups disagree on the object boundaries that things get
difficult, but for the purpose of this particular discussion I'm
trying to focus on "medium sized" objects - too big to map in a day
(or maybe too big for a single mapper to maintain), but for which
there is a broad consensus about object identity.  I'm trying to
address the Jamaica Bays, Cape Cods, and the like, which at least in
my part of the world are much commoner than any objects that have
horrible political implications.

> > > Everything else in physical geography is typically mapped locally
> > > piece by piece like the rivers and creating large features - while
> > > done by some mappers for the purpose of label painting - is
> > > generally disliked by most mappers because it is very hard to work
> > > with these and represents no additional meaningful information.
> >
> > That's where we disagree. The additional information is that the
> > multiple features represent the same physical object.
>
> And how do you verifiably determine if two things are part of the same
> physical object?  For example: [examples snipped]

I'm all for a rule of, 'if in doubt, split,' possibly paired with
creating a new relation to carry the grouping.  You seem to favour a
rule of 'never join,' which is perverse for the common case where
there is broad consensus about object identity.

> > Please avoid the term "label painting." What you call "label
> > painting" is the entirely reasonable desire to have recognized, named
> > objects appear on the map with their names.
>
> I distinguish between names and labels.  Labels are graphical
> representations of names or other strings in map renderings.  The OSM
> database should not contain labels, it should contain names.

On this, we agree. To what object should the name, 'Jamaica Bay' be
assigned? How can such an object be constructed? The locals can
clearly define its extents, except for very small indefinite
boundaries over narrow entrances and exits. What should be done to
give that object, which unquestionably is observable in the field as
an entity distinct from the ocean, existence in OSM?

The last time that we had this discussion, you dismissed wanting to
have Jamaica Bay exist as a named object as 'label painting.' I was
forced then to conclude that your definition of 'label painting' is
considerably broader than simply putting meaningless objects in the
database so that names will appear. Let it be clear: my wish for
Jamaica Bay is to identify the definite portions of its boundary
accurately, to complete its indefinite boundaries for topologic
consistency, and to have it appear in the database as the area feature
that it is, with its name. Note that I did not refer to rendering in
that request. *Part* of my wish to have the name in turn triggers a
wish to render the name. That's an ordinary human desire. Map users,
when there are objects on maps, expect to see them labeled.

Since my use of OSM does not involve intensive use of OSM-Carto, I
really consider its rendering to be secondary.  If I have the named
feature, I'll worry about how to render it in the maps I produce. If I
don't have the feature somewhere, then no conceivable rendering can
show it.  But it goes beyond rendering: I want to be able to do things
like 'gaging stations in Jamaica Bay or 

Re: [Tagging] Stop the large feature madness

[Christoph Hormann]

On Thursday 18 April 2019, marc marc wrote:
> > What if there is disagreement?
>
> it's not related to large feature, it's a issue with all
> source=local knownledge changeset (or no source at all).

No, the concept of verifiability defines a clear path for resolving 
disagreement - you verify the information on the ground and if there is 
still disagreement it is by definition something that is not verifiable 
(because several mappers evaluating the situation independently do not 
consistently come to the same results).

-- 
Christoph Hormann
http://www.imagico.de/

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Re: [Tagging] Stop the large feature madness

[marc marc]

Le 18.04.19 à 18:52, Christoph Hormann a écrit :
> What if there is disagreement?

it's not related to large feature, it's a issue with all
source=local knownledge changeset (or no source at all).
a hudge river may have a sign every km
a road in a village I like doesn't have a sign.
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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Christoph Hormann]

On Thursday 18 April 2019, Kevin Kenny wrote:
>
> And therefore the Amazon, the Nile, or the Mississippi ought not to
> be named in such a way that a large-scale map can show the names?

Map producers are obviously free to show labels however they want.  They 
don't need mappers to hand curate dedicated labeling objects for that.  
Ironically the waterway relations we have are not really of much use if 
you want to label rivers in a map.

> Essentially, you're making the statement here that if local mappers
> pool their knowledge to realize that the river in Alexandria is the
> same river in Aswan, that's a mere social convention and has no place
> on the map.

How should they determine that based on local knowledge?  What if there 
is disagreement?  Is 

https://www.openstreetmap.org/way/83015625

the same river as

https://www.openstreetmap.org/way/4769426

or

https://www.openstreetmap.org/way/174752117

or

https://www.openstreetmap.org/way/234008385

What if the local mappers do not speak the same language?  Do those who 
speak English automatically get to overrule those who don't?

> > Everything else in physical geography is typically mapped locally
> > piece by piece like the rivers and creating large features - while
> > done by some mappers for the purpose of label painting - is
> > generally disliked by most mappers because it is very hard to work
> > with these and represents no additional meaningful information.
>
> That's where we disagree. The additional information is that the
> multiple features represent the same physical object.

And how do you verifiably determine if two things are part of the same 
physical object?  For example:

https://www.openstreetmap.org/way/335279145
https://www.openstreetmap.org/way/301691395

which a map producer might want to label the Amazon Rain Forest.

Or these two:

https://www.openstreetmap.org/relation/5567277
https://www.openstreetmap.org/way/470015023

which another map producer might want to label the Eurasian Taiga.

> Please avoid the term "label painting." What you call "label
> painting" is the entirely reasonable desire to have recognized, named
> objects appear on the map with their names.

I distinguish between names and labels.  Labels are graphical 
representations of names or other strings in map renderings.  The OSM 
database should not contain labels, it should contain names.

This:

https://www.openstreetmap.org/relation/9359806

is not a named representation of a verifiable element of the geography, 
it is a labeling geometry.  Creating such is not mapping, it is label 
drawing or label painting.  It is neither meant nor suited to do 
anything other than performing a relatively simple label placement.

Note by speaking of "label painting" i do not intend to assign one sided 
blame to mappers for doing so.  In most cases this is as much the fault 
of map designers encouraging this as it is of mappers to respond to 
this incentive.

> The "hard to work with" argument is what I said is a technological
> limitation.

With "hard to work with" i was referring to work for the mapper in 
maintanance, editing and also just dealing with the object being in the 
way when editing other things.  That is not a technological limitation.

When you talked about technological limitations you were referring to 
problems of data users.

> Now, I could imagine that if the world were other than as it is,
> another culture might insist that the main stem of the river was the
> Missouri, rather than the upper MIssissippi, leading to disagreement
> about the boundaries. That disagreement could be very ugly if the
> cultures were, say, continually embroiled in political conflict about
> other matters. In that case, making a single decision about the
> boundaries might conceivably be imperialistic.

I am glad you understand the problem.  If you now look at examples 
outside the United States (where if i may say so the originally 
different cultures have been largely "homogenized" a long time ago) you 
will realize that the situation is often not that simple in other parts 
of the world.  The fact that people from more than a hundred countries 
from all over the world with very different cultures, world views and 
languages in OSM work together in collecting local knowledge despite in 
many cases not even being able to verbally communicate with each other 
is quite remarkable.  But this amazing cross cultural cooperation 
hinges on on the local verifiability of those things people map.  
Adding large scale concepts to the database that are not verifiable 
based on local knowledge means throwing a wrench into the gears of this 
amazing machine.

-- 
Christoph Hormann
http://www.imagico.de/

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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Kevin Kenny]

On Thu, Apr 18, 2019 at 5:49 AM Christoph Hormann  wrote:
> You apparently misunderstood what i said.  My 'surveyable in a single
> day by a single mapper' rule of thumb refers to mapping something as a
> single feature.  A river several thousand kilometers long for example.
> The river is locally still a verifiable element of the geography and
> can be mapped - piece by piece as it is generally established practice
> in OSM.  But if you create a feature for the whole river extending over
> thousands of kilometers that is not something you do based on local
> knowledge, that is based on social conventions you have read up in a
> book, on wikipedia or elsewhere.

And therefore the Amazon, the Nile, or the Mississippi ought not to be
named in such a way that a large-scale map can show the names?
Essentially, you're making the statement here that if local mappers
pool their knowledge to realize that the river in Alexandria is the
same river in Aswan, that's a mere social convention and has no place
on the map. Yesterday, Farouk maps one piece of its shoreline, and
today Karim maps an adjacent piece. According to your argument, those
ways ought never to be merged because ... why, exactly? Because
there's no provable single mapper with local knowledge of both of
them?  If a few dozen mappers do that, you can wind up with a feature
that's a thousand km long. They have each contributed the local name -
and it's the Nile for the entire extent, as the boatman who plies its
length could have told them.

> Everything else in physical geography is typically mapped locally piece
> by piece like the rivers and creating large features - while done by
> some mappers for the purpose of label painting - is generally disliked
> by most mappers because it is very hard to work with these and
> represents no additional meaningful information.

That's where we disagree. The additional information is that the
multiple features represent the same physical object.  Without that
information, dealing with them at large scale becomes an exercise in
ambiguity - trying to build up larger features from tiny ones, by
guessing that adjacent ones with similar attributes are parts of the
same whole. One misplaced node on a shared boundary, and the whole
thing falls apart.  That's one of several things that relations are
for - identifying that some number of small features are parts of a
larger one.

Please avoid the term "label painting." What you call "label painting"
is the entirely reasonable desire to have recognized, named objects
appear on the map with their names.  Calling it "label painting" and
saying that it provides no useful information is stating, "you
shouldn't want to work with that identified, named object, only its
parts or only some arbitrarily chosen part within it." It belittles
the user, and cuts off the conversation. There are much more
productive approaches: "I understand your want, and you can't have
that right now because we haven't worked out how to do it. Can you
help us define the needs?" is one. "That doesn't fit exactly with the
way we structure the data right now, would it be an acceptable
alternative if you were to ..." is another.

The "hard to work with" argument is what I said is a technological
limitation. If the Gulf of Aqaba - a well-defined object except for an
imaginary line across its narrow mouth - cannot be mapped because the
resulting relation would be too large, or because the data model
cannot cope with the indefiniteness of having two adjacent waterbodies
(waterbodies ordinarily do not have a well-defined bright line
separating them), that's a limitation of the data model or the tools
that work with it. Those are technological limitations, pure and
simple.

I return to an example that I used a few months ago, which I still
haven't attempted to map because largely of your and Frederik's
extremely vociferous objections: Jamaica Bay.  Let me point you to
maps that include the bay, created by skilled human cartographers:
https://caltopo.com/l/1UL6

What you see at that link includes the boundaries of several map
sheets. Note that Jamaica Bay is lettered as a prominent feature on
all of them.  The smaller features - Island Channel, Pumpkiin Patch
Channel, Grassy Bay and so on are parts of it, and are typically known
only to those who go out on the water - many land-dwellers around the
bay typically do not know their names. But the bay is known to all of
them. When I lived down that way, near https://caltopo.com/l/TPG3, my
neighbours might not know the individual parts were named Mott's
Basin, Nr Bar Channel (Nr bar is now Johnson Bar, and not a
moment too soon!) or the Head of the Bay - but everyone knew Jamaica
Bay!

If you simply left it as 'coastline' they'd look at you as if you had
two heads, and even more so if you called it the Atlantic Ocean.  The
ocean is a short distance to the south. It has pounding surf; the bay
has slack water. The ocean is salt, the bay is brackish. The bay has 

Re: [Tagging] Stop the large feature madness

[Christoph Hormann]

On Thursday 18 April 2019, Warin wrote:
>
> There are also 'points' and 'heads' to name a few other landforms
> missing in OSM.

While i have an understanding of what a mesa and a butte are i have no 
idea how you define a 'point' or 'head' so no comment on that.

> To say that they should not be mapped is to deny there existence.

No, to say some things should not be mapped acknowledges that OSM is 
about recording verifiable local knowledge and not "everything that 
exists" - whatever that means.

> It is not unusual to look for these things .. OSM failure to map them
> leads to other sources being used.

Exactly.  We need to establish that there are things outside the scope 
of OSM for which you need other projects to collect data about them.

-- 
Christoph Hormann
http://www.imagico.de/

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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Christoph Hormann]

On Thursday 18 April 2019, Kevin Kenny wrote:
>
> I doubt very much that you're saying what you intended here.
>
> It comes across as saying, for instance, that lakes too big to map on
> the ground in a single day should not be mapped, or should not be
> named. I think that making large waterbodies disappear would be
> ridiculous.

You apparently misunderstood what i said.  My 'surveyable in a single 
day by a single mapper' rule of thumb refers to mapping something as a 
single feature.  A river several thousand kilometers long for example.  
The river is locally still a verifiable element of the geography and 
can be mapped - piece by piece as it is generally established practice 
in OSM.  But if you create a feature for the whole river extending over 
thousands of kilometers that is not something you do based on local 
knowledge, that is based on social conventions you have read up in a 
book, on wikipedia or elsewhere.

As far as physical geography is concerned (so i leave out boundary and 
route relations here - which are a different thing) we have essentially 
only two types of feature that are generally accepted to be mapped with 
large relations:  lakes and islands.  Both of these were not always 
mapped this way - large lakes were for a long time mapped only 
locally - like the coastline.  Both of these are technically 
unnecessary to be mapped this way (there is no actual information 
transported in assembling the ways into an MP relation) because their 
geometry derives non-ambiguously from the locally mapped water 
outlines.  The decision to create MPs none the less mostly comes from 
the desire to have consistency with smaller features (which are 
obviously locally verifiable as a whole).

Everything else in physical geography is typically mapped locally piece 
by piece like the rivers and creating large features - while done by 
some mappers for the purpose of label painting - is generally disliked 
by most mappers because it is very hard to work with these and 
represents no additional meaningful information.

> Moreover, if you've mapped something on the ground, what difference
> does it make how long it took?

It is a rule of thumb.  The rule itself has no meaning on its own, it is 
designed to make it easy to determine a reasonable limit.

> I understand that there are fairly severe technological issues at
> present, where a plethora of enormous multipolygons breaks some of
> the software tools.

My argument is not a technological one, it is a social one.  Mapping 
only things verifiable based on local knowledge in OSM is essential for 
the social cohesion of the project across many different cultures world 
wide without creating an imperialistic dominance of some cultures over 
others.

-- 
Christoph Hormann
http://www.imagico.de/

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Re: [Tagging] Stop the large feature madness

[Mateusz Konieczny]

Apr 18, 2019, 12:12 AM by graemefi...@gmail.com:

>
>
> On Thu, 18 Apr 2019 at 03:35, Michael Patrick <> geodes...@gmail.com 
> > > wrote:
>
>> our map would look like this :-)   >> http://bit.ly/2IGkgoj 
>> 
>>
>
> That's an amazing image, thanks Michael.
>
> I take it that's the home location of all OSM contributors?
>
missing legend is missing, but for me it looks like world map limited to areas 
with
population density (of all humans, not just OSM mappers) above some threshold.

Maybe flooded areas are officially uninhabited.
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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Kevin Kenny]

On Wed, Apr 17, 2019 at 7:55 AM Christoph Hormann  wrote:
> As a rule of thumb i'd say something that can at least coarsely be
> surveyed on the ground by a single mapper during a single day is
> usually suitable to be mapped as a distinct named feature, provided it
> is otherwise verifiable of course.  For larger things mapping should
> focus on locally mapping locally surveyable constituent parts or
> aspects of the feature but i would be very careful with creating
> features for them as a whole because this very often drifts from the
> OSM idea of mapping local knowledge to a Wikipedia-like recording of
> social conventions.

I doubt very much that you're saying what you intended here.

It comes across as saying, for instance, that lakes too big to map on
the ground in a single day should not be mapped, or should not be
named. I think that making large waterbodies disappear would be
ridiculous.

Moreover, if you've mapped something on the ground, what difference
does it make how long it took?  It took me a number of trips over many
days to gather the GPS tracks that were consolidated into
https://www.openstreetmap.org/relation/4286650. (It was initially
planned as a single trip with two stops for resupply, but the best
laid plans gang aft agley.) On one of those trips I was in the field
for six days straight, and was at times thirty km from the nearest
drivable road. Of course the relation has many constituent ways,
because of tagging for things like bridge=yes or ford=yes, changes of
surface=*, brief stretches where the trail follows a road, and similar
changes. Moreover, I intentionally broke the ways up so as not to have
thousands of nodes on any signle way. But on the ground, the relation
represents a single trail. It has the same name for its entire length
(and is signed where it shares the way with a highway). Is it less
worthy of mapping because in order to order to map one section, I had
to lug enough batteries to keep my GPS going (and enough food to keep
Kevin going) for six days?

Surely you're not arguing that I can't have 'local knowledge' of it
when I've personally had my literal boots on the literal ground for
every step of the way?

I understand that there are fairly severe technological issues at
present, where a plethora of enormous multipolygons breaks some of the
software tools. For now, therefore, I refrain from mapping anything
like the Long Island Sound or the Red Sea as areas, even though I
believe that competent label placement in some renderings will require
that eventually. Similarly, I'm not about to go mapping enormous
linear features or area features for the Mogollon Plateau, the
Catskill Mountains, or the Great Dismal Swamp, The software will catch
up in time, and in the meantime I'll try to be a good neighbour and
not break things; I can experiment on my own database with my own
toolchain. But some large features are unavoidable: I'm not giving up
Lake Champlain or the Adirondack Park just because of their immense
size.

I understand that relations with a vast number of members are also
problematic, which is why I introduced a further level of breakdown
into sections on the not-quite-finished project to map
https://www.openstreetmap.org/relation/919642 .  I try to be a good
citizen with large objects, but there are large definite objects in
the field, and a rule like "no bigger than a day's walk" is going to
leave us with an urban-only map.

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Re: [Tagging] Stop the large feature madness

[Warin]

On 18/04/19 00:02, Christoph Hormann wrote:

On Wednesday 17 April 2019, Joseph Eisenberg wrote:

I believe many people are using natural=peak to add the name of
plateaus / mesas / tablelands.

Yes, that is definitely the case for buttes and small mesas - but then
again these are features that can be verifiably mapped based on local
knowledge.  However using a generic natural=plateau tag which is then
inevitably used by some mappers to cargo cult polygons around just
about any area of land elevated in some way relative to its surrounding
is not a good idea.


There are also 'points' and 'heads' to name a few other landforms missing in 
OSM.

To say that they should not be mapped is to deny there existence.
It is not unusual to look for these things .. OSM failure to map them leads to 
other sources being used.

If large features are not to be mapped in OSM then most countries will have to 
be removed. :P




I see nothing wrong with creating natural=butte and natural=mesa with
appropriately tight definitions:  Both being surrounded on all sides by
cliffs or very steep slopes, buttes with a height larger than width and
mesas with a flat top (i.e. height variation across the top being
significantly smaller than the total height).




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Re: [Tagging] Stop the large feature madness

[Daniel Koć]

W dniu 17.04.2019 o 21:47, Mateusz Konieczny pisze:
> Apr 17, 2019, 7:34 PM by geodes...@gmail.com:
>
> If everyone on Earth joined OSM and limited their mapping
> to their own local knowledge using that rule of thumb, our map
> would look like this :-)   http://bit.ly/2IGkgoj
>
Nice and funny illustration of OSM problems with global and remote
natural areas. How did you create it?


> Nobody proposed ban on mapping things far away from your place of
> residence.


That would probably only add to this picture some spots (remote
settlements and touristic attractions) and thin lines (along routes).
And probably only spots, if single day would be the limit.

OSM started as a very local enterprise, but the world is much wider, so
we should rethink how to deal with them, because the world is not gonna
shrink...


-- 
"I see dead people" [Sixth Sense]

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Re: [Tagging] Stop the large feature madness

[Graeme Fitzpatrick]

On Thu, 18 Apr 2019 at 03:35, Michael Patrick  wrote:

> our map would look like this :-)   http://bit.ly/2IGkgoj
>

That's an amazing image, thanks Michael.

I take it that's the home location of all OSM contributors?

I'm surprised that India & especially China (where I thought OSM was
banned?) are covered so well, & also a bit surprised that Australia & NZ
have dropped back into the Ocean - I thought there were a few more of us
than that? - us few seem to have done a pretty good job then!

(cc'ed to AU list for interest's sake :-))

Thanks

Graeme



> Also, in regard to how 'sharp' the boundaries some of these
> very large features are, if a person has a passing knowledge
> of 'road cut' geology and mineralogy, they are incredibly
> distinct, especially in the American Southwest. They are
> also identifiable from DEM/DSM analysis, sometimes as
> easily as coloring the elevation.
>
> I somewhat agree that 'if' it was at all to go into OSM,
> there would be a special interest group that would
> ride herd on a specialized name space. These geologic
> regions are essentially 'historical' features, some on
> the order of a billion years :-)
>
> Michael
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Re: [Tagging] Stop the large feature madness

[Mateusz Konieczny]

Apr 17, 2019, 7:34 PM by geodes...@gmail.com:

> > ... As a rule of thumb i'd say something that can at least coarsely be 
> > surveyed on the ground by a single mapper during a single day is 
> > usually suitable to be mapped as a distinct named feature, provided it 
> > is otherwise verifiable of course.  ... 
>
> If everyone on Earth joined OSM and limited their mapping 
> to their own local knowledge using that rule of thumb, our map 
> would look like this :-)   > http://bit.ly/2IGkgoj 
>
Nobody proposed ban on mapping things far away from your place of residence. 

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[Tagging] Stop the large feature madness

[Michael Patrick]

> ... As a rule of thumb i'd say something that can at least coarsely be
> surveyed on the ground by a single mapper during a single day is
> usually suitable to be mapped as a distinct named feature, provided it
> is otherwise verifiable of course.  ...

If everyone on Earth joined OSM and limited their mapping
to their own local knowledge using that rule of thumb, our map
would look like this :-)   http://bit.ly/2IGkgoj

Also, in regard to how 'sharp' the boundaries some of these
very large features are, if a person has a passing knowledge
of 'road cut' geology and mineralogy, they are incredibly
distinct, especially in the American Southwest. They are
also identifiable from DEM/DSM analysis, sometimes as
easily as coloring the elevation.

I somewhat agree that 'if' it was at all to go into OSM,
there would be a special interest group that would
ride herd on a specialized name space. These geologic
regions are essentially 'historical' features, some on
the order of a billion years :-)

Michael
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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Christoph Hormann]

On Wednesday 17 April 2019, Joseph Eisenberg wrote:
>
> I believe many people are using natural=peak to add the name of
> plateaus / mesas / tablelands.

Yes, that is definitely the case for buttes and small mesas - but then 
again these are features that can be verifiably mapped based on local 
knowledge.  However using a generic natural=plateau tag which is then 
inevitably used by some mappers to cargo cult polygons around just 
about any area of land elevated in some way relative to its surrounding 
is not a good idea.

I see nothing wrong with creating natural=butte and natural=mesa with 
appropriately tight definitions:  Both being surrounded on all sides by 
cliffs or very steep slopes, buttes with a height larger than width and 
mesas with a flat top (i.e. height variation across the top being 
significantly smaller than the total height).

-- 
Christoph Hormann
http://www.imagico.de/

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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Andrew Harvey]

On Wed, 17 Apr 2019 at 23:04, Joseph Eisenberg 
wrote:

> ...These would actually be an example of a feature
> that does have a verifiable border, and could therefore be mapped as
> an area by following the top of the cliff all the way around, but I
> don't see any great benefit to doing all that work to copy the path of
> the natural=cliff, when a node at the center of the feature will do.
>

I would always see a node as just a temporary approach to map a plateau in
place of a closed way.

The advantage of a way is renders get a sense of size of the feature and
can decide at which zoom level to label it. It also helps for building
reverse geocoders so they can say you're on X plateau when inside the area.
Neither really possible with just a node.
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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Joseph Eisenberg]

I did not intend to encourage mappers to start adding giant
multipolygons for the Tibetan plateau or the Colorado Plateau. In fact
I'm doing my best to discourage mappers from adding non-verifiable,
huge areas to the database: see
https://github.com/gravitystorm/openstreetmap-carto/pull/3750

I asked about an appropriate tag for tablelands / mesas / plateaus
after finding that several place=locality nodes in Andorra are used to
map features named "Pla de *” (x2) and "Planell(s) *" (x3), both of
which are likely types of plateau, if I'm reading the Catalan
dictionary correctly. It would be nice if many of the place=locality
nodes could be updated to a more specific tag, and there didn't seem
to be anything that fit other than natural=plateau.

Personally, I don't plan to add any closed ways, let alone
multipolgyons, to map large plateaus, though I will check if the Table
Rocks near Medford OR are tagged correctly:
https://en.wikipedia.org/wiki/Upper_and_Lower_Table_Rock - tablelands
about 1 and 2 square miles in size with clearly defined borders
(cliffs) on all sides. These would actually be an example of a feature
that does have a verifiable border, and could therefore be mapped as
an area by following the top of the cliff all the way around, but I
don't see any great benefit to doing all that work to copy the path of
the natural=cliff, when a node at the center of the feature will do.

I believe many people are using natural=peak to add the name of
plateaus / mesas / tablelands. This may be acceptable for buttes,
where the flat top of the hill is small, but for a 1 or 2 kilometer
width plateau there may be several topographical peaks, while the name
may refer to the whole flat topped mountain.

(For most mountains natural=ridge is an verifiable alternative when
the name is not actually associated with a particular peak, but some
tablelands are flat enough that a mapper could not be expected to
identify a ridge or a particular peak)

I planned to document the use of natural=plateau - I will suggest that
multipolgyons be avoided and that the tag not be used to map
non-verifiable geometries, like the Columbia plateau, the Altiplano,
or any of the other huge plateaus listed here:
https://en.wikipedia.org/wiki/Plateau#Large_plateaus - these all are
vaguely bordered by hills, mountains and lowlands, quite different
from a small tableland surrounded by cliffs on all sides.

On 4/17/19, Christoph Hormann  wrote:
> On Wednesday 17 April 2019, Frederik Ramm wrote:
>> [...]
>>
>> The way OSM usually works is someone stumbles over something in
>> reality, with a discernible name or property, and adds it to OSM. We
>> are, first and foremost, surveyors.
>>
>> The larger a feature becomes, the less suitable OSM is for mapping
>> it. And in the case of the several large-scale objects I have
>> mentioned, most contributors don't even have surveying in mind, but
>> just writing down existing conventions.
>
> Indeed.  We should always keep in mind that OSM is fundamentally about
> collecting local knowledge of the geography.  'local' is key here.  If
> you try to map some geometry for the Altiplano or the Tibet Plateau
> that is not local knowledge.
>
> As a rule of thumb i'd say something that can at least coarsely be
> surveyed on the ground by a single mapper during a single day is
> usually suitable to be mapped as a distinct named feature, provided it
> is otherwise verifiable of course.  For larger things mapping should
> focus on locally mapping locally surveyable constituent parts or
> aspects of the feature but i would be very careful with creating
> features for them as a whole because this very often drifts from the
> OSM idea of mapping local knowledge to a Wikipedia-like recording of
> social conventions.
>
> Some of the things Joseph mentioned (like buttes) are certainly mappable
> in OSM under this rule - but i'd suggest creating specific well defined
> tags with a precise and tight definition for them and not a generic tag
> for any elevated region.
>
> In any case i think the most valuable thing to map of any of such is the
> constituent elements and aspects of it like natural=cliff,
> natural=arete, natural=peak, natural=bare_rock, natural=scree etc.
>
> --
> Christoph Hormann
> http://www.imagico.de/
>
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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Tomas Straupis]

And here the idea of a new separate data layer (as in GIS) for geometries
of fuzzy features rises again... 
Waiting for its time.
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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Christoph Hormann]

On Wednesday 17 April 2019, Frederik Ramm wrote:
> [...]
>
> The way OSM usually works is someone stumbles over something in
> reality, with a discernible name or property, and adds it to OSM. We
> are, first and foremost, surveyors.
>
> The larger a feature becomes, the less suitable OSM is for mapping
> it. And in the case of the several large-scale objects I have
> mentioned, most contributors don't even have surveying in mind, but
> just writing down existing conventions.

Indeed.  We should always keep in mind that OSM is fundamentally about 
collecting local knowledge of the geography.  'local' is key here.  If 
you try to map some geometry for the Altiplano or the Tibet Plateau 
that is not local knowledge.

As a rule of thumb i'd say something that can at least coarsely be 
surveyed on the ground by a single mapper during a single day is 
usually suitable to be mapped as a distinct named feature, provided it 
is otherwise verifiable of course.  For larger things mapping should 
focus on locally mapping locally surveyable constituent parts or 
aspects of the feature but i would be very careful with creating 
features for them as a whole because this very often drifts from the 
OSM idea of mapping local knowledge to a Wikipedia-like recording of 
social conventions.

Some of the things Joseph mentioned (like buttes) are certainly mappable 
in OSM under this rule - but i'd suggest creating specific well defined 
tags with a precise and tight definition for them and not a generic tag 
for any elevated region.

In any case i think the most valuable thing to map of any of such is the 
constituent elements and aspects of it like natural=cliff, 
natural=arete, natural=peak, natural=bare_rock, natural=scree etc.

-- 
Christoph Hormann
http://www.imagico.de/

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Re: [Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Mateusz Konieczny]

Apr 17, 2019, 11:29 AM by frede...@remote.org:

> I think we all should stop seeking out one large-scale feature type
> after the other that is "missing" from OSM and think about how to best
> add them. In my view, the fact that these are underrepresented in OSM is
> not an opportunity to "improve" OSM but a sign that OSM isn't the right
> place for that kind of data.
>
> Instead, let us find a way of recording such imprecise information
> outside of OSM's data model, and make it easy to access it e.g. when
> rendering maps.
>
Especially as such features are subjective, with multiple competing definitions
and local survey is not adding anything useful.

For example splitting Earth's oceanic waters into oceans is subjective, 
mapping one selected division or all of them is not useful in OpenStreetMap

See
https://commons.wikimedia.org/wiki/File:World_ocean_map.gif 

for multiple splits of oceans, see
https://en.wikipedia.org/wiki/Boundaries_between_the_continents_of_Earth 

is similar, the same happens with mountain ranges and other 
similar large-scale features.

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[Tagging] Stop the large feature madness (was: Tag for a plateau or tableland?)

[Frederik Ramm]

Josh & others,

I think we need to take a break here from making OSM into a map of
large-scale geographic features.

This is getting out of hand. I vividly remember the endless discussions
about bays and peninsulae. Drainage basins. Now plateaus. I don't
remember mountain ranges in the recent past but if they weren't
discussed then they surely are next.

The way OSM usually works is someone stumbles over something in reality,
with a discernible name or property, and adds it to OSM. We are, first
and foremost, surveyors.

The larger a feature becomes, the less suitable OSM is for mapping it.
And in the case of the several large-scale objects I have mentioned,
most contributors don't even have surveying in mind, but just writing
down existing conventions. I haven't checked, but I would be very
surprised if *anyone* actually used the natural=peninsula tag for
something they happen to identify as a peninsula - no, natural=peninsula
is just a method of putting existing geographical names into OSM
(because the fact that something is a peninsula can be auto-detected).
Same with your plateaus and tablelands now - do you really envisage
someone looking at the landscape around them and saying "why, there's a
hard layer of rock here on top of softer layers, and a couple cliffs at
the sides, I guess I'll map this as a plateau"? No, again this is a
situation where you have third-party information about a plateau (and
likely its name) and are looking for ways to get that into OSM.

All these requests are born from a desire to write down existing
large-scale geological/geographical knowledge. But OSM is ill suited for
that; OSM cannot accommodate imprecise features. If you want to map a
mesa well in OSM then it has to be detectable on the ground, and it has
to have a clearly delineated boundary. What you are trying to do here is
adding large-scale features that come in handy when you want to make a
map ata  1:10m or maybe 1:50m scale. Projects like naturalearthdata.com
are ideally suited for that kind of data. OpenStreetMap is not.

I think we all should stop seeking out one large-scale feature type
after the other that is "missing" from OSM and think about how to best
add them. In my view, the fact that these are underrepresented in OSM is
not an opportunity to "improve" OSM but a sign that OSM isn't the right
place for that kind of data.

Instead, let us find a way of recording such imprecise information
outside of OSM's data model, and make it easy to access it e.g. when
rendering maps.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frede...@remote.org  ##  N49°00'09" E008°23'33"

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