Re: [Tagging] RFC proposed water property key 'ephemeral '

[Mateusz Konieczny]

31. May 2018 01:02 by 61sundow...@gmail.com :


> I will not beusing the 'intermittent' tag again. 




 That is OK, as long as you will not remove correct intermittent tags added by 
others.

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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Warin]

On 30/05/18 21:55, Mateusz Konieczny wrote:
30. May 2018 00:31 by 61sundow...@gmail.com 
:


In that case I would tag

intermittent=summer


(...)

The tags should 'make sense' without requiring further explanation
... as that generates these kind of problems. 




I strongly oppose bolting on additional unclear values to tag where 
99.99% values are yes/no.



See https://taginfo.openstreetmap.org/keys/intermittent#values 98.68% 
for yes, 1.31% for no,


all other values together 0.01%.


Especially as intermittent=summer may easily mean:


"intermittent during summer, water present otherwise"

"intermittent during summer, no water otherwise"


Intermittent is nice, clean tag without overly complicated syntax and 
it should stay this way.




The question asked was 'how would you tag it'.

I answered how I would tag it. Note - with the increased use of 
'intermittent' as a way of having seasonal rendered I will not be using 
the 'intermittent' tag again.

In fact I see it as a nonsense tag due to its multiple OSM meanings.
So i will be using tags that are more tightly defined .. like seasonal 
(by it self).
If renders chose not to render the tag seasonal that is their choice, 
not up to mappers to use another tag to have it rendered.


-
I take it there are not further comments on the topic (the subject of 
this thread) of 'ephemeral'?



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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Mateusz Konieczny]

30. May 2018 00:31 by 61sundow...@gmail.com :


> In that case I would tag
> 
> intermittent=summer 
> 

 


(...)


 

> The tags should 'make sense' without requiring further explanation... as 
> that generates these kind of problems. 







I strongly oppose bolting on additional unclear values to tag where 99.99% 
values are yes/no.




See https://taginfo.openstreetmap.org/keys/intermittent#values 
 98.68% for yes, 
1.31% for no,

all other values together 0.01%.




Especially as intermittent=summer may easily mean:




"intermittent during summer, water present otherwise"

"intermittent during summer, no water otherwise"




Intermittent is nice, clean tag without overly complicated syntax and it should 
stay this way.



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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Mateusz Konieczny]

30. May 2018 07:23 by osm.tagg...@thorsten.engler.id.au 
:
> intermittent=summer
> In summer: explicit state = intermittent
>
> Otherwise: default state = not present
>




I strongly oppose bolting on additional unclear values to tag where 99.99% 
values are yes/no.




See https://taginfo.openstreetmap.org/keys/intermittent#values 
 98.68% for yes, 
1.31% for no,

all other values together 0.01%.




Especially as intermittent=summer may easily mean:




"intermittent during summer, water present otherwise"

"intermittent during summer, no water otherwise"




Intermittent is nice, clean tag without overly complicated syntax and it should 
stay this way.




One may easily invent new tags to properly tag such detail.

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Re: [Tagging] RFC proposed water property key 'ephemeral '

[osm.tagging]

I would like to repeat (slightly extended) the contents of my previous post of 
how to interpret these tags:

 

The default state (no tags) is:

water (usually) always present

 

The seasonal, intermittent and ephemeral tags (allowing season or month 
timeframes in addition to yes) say:

 

The value yes and no define a new default state for the whole year (based on 
tag).

 

Other values define:

For these times, the explicit state is: the water (usually) always present, is 
intermittent, or is ephemeral

For all other times, the default state is: (usually) never present.

 

Always present overrides intermittent overrides ephemeral overrides not present.

Explicit state always overwrites default state.

 

These specific rules would result in exactly the interpretation you’ve given 
below.

 

intermittent=summer

In summer: explicit state = intermittent

Otherwise: default state = not present

 

intermittent=yes

default state = intermittent

 

seasonal=summer

in summer: explicit state= always present

otherwise: default state = not present

 

in combination:

in summer: explicit state= always present

otherwise: default state = intermittent

 

From: Warin <61sundow...@gmail.com> 
Sent: Wednesday, 30 May 2018 08:32
To: tagging@openstreetmap.org
Subject: Re: [Tagging] RFC proposed water property key 'ephemeral '

 

On 29/05/18 20:52, Paul Allen wrote:

On Tue, May 29, 2018 at 12:06 AM, Warin <61sundow...@gmail.com 
<mailto:61sundow...@gmail.com> > wrote:


Adding intermittent=yes to seasonal=yes adds no usefull information either. 

That depends how you interpret it.  Which would depend, to some extent, how it 
was documented. 

The seasonal=yes says it is non perennial all by it self. 

 

You're interpreting seasonal as being a specific case of intermittent: 
sometimes there is water

and sometimes there isn't; the water is present (for example) in summer but not 
other times of year.

 

Try this alternative interpretation which is meaningful: there is water there 
in summer but not

at other times of year however, even in summer, that flow is intermittent.


In that case I would tag

intermittent=summer 

The tag is much clear than 
intermittent=yes 
seasonal=summer
that could be taken (and how I would interpret it) to have a summer water 
presence with intermittent water at other times of the year. 




 

That, i think, would make such a combination meaningful.  Not necessarily how 
people

would interpret it without further explanation, which would be an argument 
against such

use, but meaningful.


The tags should 'make sense' without requiring further explanation ... as that 
generates these kind of problems. 

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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Warin]

On 29/05/18 20:52, Paul Allen wrote:
On Tue, May 29, 2018 at 12:06 AM, Warin <61sundow...@gmail.com 
> wrote:



Adding intermittent=yes to seasonal=yes adds no usefull
information either.

That depends how you interpret it.  Which would depend, to some 
extent, how it was documented.


The seasonal=yes says it is non perennial all by it self.


You're interpreting seasonal as being a specific case of intermittent: 
sometimes there is water
and sometimes there isn't; the water is present (for example) in 
summer but not other times of year.


Try this alternative interpretation which is meaningful: there is 
water there in summer but not

at other times of year however, even in summer, that flow is intermittent.


In that case I would tag

intermittent=summer

The tag is much clear than
intermittent=yes
seasonal=summer
that could be taken (and how I would interpret it) to have a summer 
water presence with intermittent water at other times of the year.




That, i think, would make such a combination meaningful.  Not 
necessarily how people
would interpret it without further explanation, which would be an 
argument against such

use, but meaningful.


The tags should 'make sense' without requiring further explanation ... 
as that generates these kind of problems.
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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Paul Allen]

On Tue, May 29, 2018 at 12:06 AM, Warin <61sundow...@gmail.com> wrote:

>
> Adding intermittent=yes to seasonal=yes adds no usefull information
> either.
>
> That depends how you interpret it.  Which would depend, to some extent,
how it was documented.

The seasonal=yes says it is non perennial all by it self.
>

You're interpreting seasonal as being a specific case of intermittent:
sometimes there is water
and sometimes there isn't; the water is present (for example) in summer but
not other times of year.

Try this alternative interpretation which is meaningful: there is water
there in summer but not
at other times of year however, even in summer, that flow is intermittent.

That, i think, would make such a combination meaningful.  Not necessarily
how people
would interpret it without further explanation, which would be an argument
against such
use, but meaningful.

-- 
Paul
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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Mateusz Konieczny]

29. May 2018 01:06 by 61sundow...@gmail.com :


> > On 29/05/18 01:47, Mateusz Konieczny  wrote:
> > 
>> 
>>   
>>   
>>   28. May 2018 02:22 by >> 61sundow...@gmail.com 
>> >> :
>>   
>>   
>>> Why not add thetag water=yes to all waterways and lakes etc?
>>>   
>>   
>>
>>   
>>   
>> Because it adds no useful info?
>> 
> 
> Adding intermittent=yes to seasonal=yes adds no usefull information
> either. 
> 
> The seasonal=yes says it is non perennial all by it self. 



Note that typical edit goes other way - adding seasonal tag where 
intermittent=yesis already present (and I am not fan of replacing existing 
correct tag by a new one -typically it is better to keep both general and 
detailed one).
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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Warin]

On 29/05/18 01:47, Mateusz Konieczny wrote:




28. May 2018 02:22 by 61sundow...@gmail.com 
:


Why not add the tag water=yes to all waterways and lakes etc?


Because it adds no useful info?



Adding intermittent=yes to seasonal=yes adds no usefull information either.

The seasonal=yes says it is non perennial all by it self.
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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Alan Grant]

>
> > From: Mateusz Konieczny 
>
> > I consider it as an useful information to distinguish permanent
> waterways and waterbodies
>
> > from nonpernament.
>

I agree. As a point of reference, the standard 1:25000 topographic maps of
Spain produced by IGN, the national geographic institute, distinguishes
between these two categories of water course. In the legend they are
labelled as "curso de agua: permanente, intermitente". I think that is a
good indication that this is a meaningful distinction. And I believe it is
very similar to how things are already mapped in OSM.

It is fine to give mappers ways to add finer details of seasonality,
ephemerality and so on, but the basic distinction that already exists seems
to be useful in its own right.

As an aside, dictionary definitions of "intermittent" tend to say something
like  "occurring occasionally or at regular or irregular intervals" (example
from Collins) which covers all forms of non-permanence, seasonal or
otherwise. So current OSM usage of the tag, as well as being meaningful and
useful, matches usage in everyday English.
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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Mateusz Konieczny]

28. May 2018 02:22 by 61sundow...@gmail.com :


> Why not add the tag water=yes to all waterways and lakes etc?
>




Because it adds no useful info?

 


> About as usefull as the tag intermittent now as it means any waterway that 
> might not have water in it .. at any time.
>
> Most waterways dry up in droughts .. so even those waterways regarded as 
> perennial can now be tagged intermittent.
>




Everything tagged in OSM is not true in extreme situation. Car crash may cause 
passable road to

not be passable, tunnel may be blocked by an avalanche, shop may be closed 
during strike,

waterway may have no water during unusual extreme drought or during some weird

hydro-engineering like dropping outflow from a dam to zero.


 

> So I now regard the intermittent tag as having no usefull information




I consider it as an useful information to distinguish permanent waterways and 
waterbodies

from nonpernament.

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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Warin]

On 27/05/18 21:47, Christoph Hormann wrote:

On Sunday 27 May 2018, Mateusz Konieczny wrote:

One problem about this proposal is that it implies the proposed tag
and intermittent=* are mutually exclusive.  This as said simply
clashes with the current reality of tagging.

ouch, intended meaning was exactly opposite

What you wrote was clear, i was talking about Warin's proposal which
implies ("This should not be confused with intermittent") that you
should either tag intermittent=* or ephemeral=* but not both.


Intermittent is now being added to all seasonal tagged water things  ...

By adding 'ephemeral' to intermittent means that intermittent has even 
less to distinguish it.



Why not add the tag water=yes to all waterways and lakes etc?

About as usefull as the tag intermittent now as it means any waterway 
that might not have water in it .. at any time.


Most waterways dry up in droughts .. so even those waterways regarded as 
perennial can now be tagged intermittent.


So I now regard the intermittent tag as having no usefull information - 
it could mean anything. And I give up on having it made sensible in any way.



--

Is it agreed that the proposed tag 'ephemeral' should not be confused 
with the tag 'seasonal'?














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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Christoph Hormann]

On Sunday 27 May 2018, Mateusz Konieczny wrote:
> >
> > One problem about this proposal is that it implies the proposed tag
> > and intermittent=* are mutually exclusive.  This as said simply
> > clashes with the current reality of tagging.
>
> ouch, intended meaning was exactly opposite

What you wrote was clear, i was talking about Warin's proposal which 
implies ("This should not be confused with intermittent") that you 
should either tag intermittent=* or ephemeral=* but not both.

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

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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Mateusz Konieczny]

27. May 2018 11:45 by o...@imagico.de :


> On Sunday 27 May 2018, Mateusz Konieczny wrote:
>>
>> I attempted to add something from this very useful summary to wiki in
>
> Yes, saw it.
>
> One problem about this proposal is that it implies the proposed tag and 
> intermittent=* are mutually exclusive.  This as said simply clashes 
> with the current reality of tagging.




ouch, intended meaning was exactly opposite




https://wiki.openstreetmap.org/w/index.php?title=Key:intermittent=1612649=1612603
 





attempted to fix this

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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Christoph Hormann]

On Sunday 27 May 2018, Mateusz Konieczny wrote:
>
> I attempted to add something from this very useful summary to wiki in

Yes, saw it.

One problem about this proposal is that it implies the proposed tag and 
intermittent=* are mutually exclusive.  This as said simply clashes 
with the current reality of tagging.

Creating a supplemental tag (ephemeral=yes or intermittent=ephemeral or 
anything else) would seem fine to me if it is well defined what it 
means and if there is a clear warning on verifiability (i.e. that you 
should only use it if you have realiable local knowledge of the 
ephemeral nature).

By the way about 100k of the 150k features with a seasonal=* tag also 
have an intermittent tag and the ~50k which do not include all the 
seasonal roads etc.  So seasonal=* is for water features mostly used as 
a supplemental tag to intermittent=*.

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

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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Mateusz Konieczny]

25. May 2018 11:42 by o...@imagico.de :


> On Friday 25 May 2018, Warin wrote:
>>
>> Intermittent does not equal ephemeral.
>
> So you have said repeatedly.
>
> I know this is hard for native English speakers but you need to accept 
> that tags in OSM do not generally mean what the English language terms 
> they use mean.
>
> intermittent=yes in OSM currently means quite precisely what the OSM 
> wiki says it means:
>
> "The intermittent=* key is used to indicate that a body of water does 
> not permanently contain water."
>
> This includes at least a few 100k features you would define as 
> ephemeral.  You can't change that with a proposal.




I attempted to add something from this very useful summary to wiki in

https://wiki.openstreetmap.org/w/index.php?title=Key:intermittent=1612599=1610066
 


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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Warin]

On 25/05/18 20:09, Nick Bolten wrote:
> The tag provides mapper a way of tagging rivers and streams that is 
presently not available.


> That will vary .. year to year and decade to decade ... to much change?

> This too will vary.

I think something might be getting lost in translation, since those 
questions were rhetorical. I'm describing my understanding of the 
proposal as it exists on the wiki, hoping it matches the intent.


> Intermittent does not equal ephemeral.

I now understand that after reading a few reviews, but the wiki 
proposal does not make that very clear. From the wiki articles, an 
ephemeral body of water "is only present for short duration", and 
intermittent "is used to indicate that a body of water does not 
permanently contain water". From those definitions alone, I'd assume 
that a river could have both `intermittent=yes` and `ephemeral=yes` 
and be perfectly valid. However, my new and improved understanding of 
hydrology definitions would say these are separate and incompatible 
categories of rivers/streams. Page 6 of this EPA document [1] has 
definitions that make these things clearer, maybe a similar approach 
could be taken with the wiki.

The proposal clearly says under 'definition'
"A property key for water that is only present for short duration. 
‘Short duration’ is typically less than 1 day for each flow. The 
majority of the time, at least 90% of the time, the water is not present."


The key thing for ephemeral is 'short duration' ... and 'dry most of the 
time' ... those words do not exist for 'intermittent' nor 'seasonal' in 
the OSM wiki.




> At present in OSM the tag to indicate an  intermittent flow that only 
occurs in winter isintermittent=winter


> The proposal for ephemeral flow in autumn would be
ephemeral=autumn

> Combining these would give
> intermittent=winter
> ephemeral=autumn

> I would think that is easy enough to understand and matches the 
present tagging scheme in use.


This is actually undocumented, and taginfo has no examples of seasons 
being used as values for the `intermittent` key. With that said, I was 
also suggesting that seasons might more appropriately be values for 
keys describing "frequency/type of flow" like `intermittent` or 
`ephemeral`, rather than having a separate `seasonal` tag, due to the 
ambiguity of having more than one flow mode over the duration of a 
year. Something like `intermittent:seasonal=` might also work. 
Maybe I'm missing a proposal for seasonal values for `intermittent`?


The key 'intermittent' is poorly defined.
I am not proposing to alter that here (I have another thread on 
seasonal, intermittent and ephemeral, suggest that be used for that kind 
of discussion).





The idea I'm proposing is that there may be a 'catch-all' key that 
describes the 'type' of thing that `ephemeral` or `intermittent` are, 
and to set `intermittent`, `ephemeral`, or otherwise (`perennial`?) 
values when appropriate. What about `flow=ephemeral` or 
`flow=intermittent`? Then, if you need to set more specifics, you 
could use `flow:ephemeral=winter`. This also provides a convenient 
hint for what is being described: the flow type of the stream.


1) these keys can also be applied to lakes .. where 'flow' is not what 
is wanted.



> The intermittent tag already exists .. do you want to change it?

I think we're both considering changes to the `intermittent` tag as 
potential options.


> And what if the stream has a seasonal flow in say winter and an 
ephemeral flow possible in spring?

> For this proposal this would be tagged
> seasonal=winter
> ephemeral=spring

This is super confusing. Namely, the `seasonal` tag's documentation 
indicates whether the feature is present, but in this case it seems to 
be indicating that there is a 'full' flow
No.. is says water is present .. not quantifying the rate of flow or the 
depth of water in a lake. It says water is present ... nothing else.
I can see nothing in the OSK wiki for seasonal that says it is full 
flow. Or any set flow rate.


There is no proposal to tag flow rates .. if you want to do that you 
propose it.


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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Warin]

On 25/05/18 19:42, Christoph Hormann wrote:


On Friday 25 May 2018, Warin wrote:

Intermittent does not equal ephemeral.

So you have said repeatedly.

I know this is hard for native English speakers but you need to accept
that tags in OSM do not generally mean what the English language terms
they use mean.


The English language has a lot of words, the choice should be made for matching 
the required meaning with a word.



intermittent=yes in OSM currently means quite precisely what the OSM
wiki says it means:

"The intermittent=* key is used to indicate that a body of water does
not permanently contain water."

This includes at least a few 100k features you would define as
ephemeral.  You can't change that with a proposal.

There is a reason why such a broad and undifferentiated tag has become
popular in OSM despite there being more differentiated concepts in
existence:  Because more differentiation here is in many cases
practically non-verifiable.  No matter if mappers observe on the ground
or via images, the usual case is they see the waterbody in a dry state
but see clear indications of recent water cover or water flow hence
they can assume a non-permanent waterbody.  This is what you can
currently indicate via intermittent=yes.

But requiring mappers to guess what kind of time pattern the change from
dry to water cover follows does not work.  Offering this as an option
in case mappers have more in depth knowledge is a good idea, i said
that in the past.  But making it mandatory is bound to fail.


I am trying to tightly define ephemeral so that it cannot be confused or used 
with with intermittent nor with seasonal.
If ephemeral is taken as being equal to intermittent than there is no point in 
having the key.
If a mapper cannot determine that something is ephemeral  then don't use 
it! Simple.
Leave ephemeral for those that can determine it.
 
I do not require that all mappers use it.

That would be like having all mappers not use sport=multi but detail each sport 
using the ; as a separator.
There is no requirement to use or not use a tag. By providing the tag the data 
can have more detail when that detail is avalible.


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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Nick Bolten]

> The tag provides mapper a way of tagging rivers and streams that is
presently not available.

> That will vary .. year to year and decade to decade ... to much change?

> This too will vary.

I think something might be getting lost in translation, since those
questions were rhetorical. I'm describing my understanding of the proposal
as it exists on the wiki, hoping it matches the intent.

> Intermittent does not equal ephemeral.

I now understand that after reading a few reviews, but the wiki proposal
does not make that very clear. From the wiki articles, an ephemeral body of
water "is only present for short duration", and intermittent "is used to
indicate that a body of water does not permanently contain water". From
those definitions alone, I'd assume that a river could have both
`intermittent=yes` and `ephemeral=yes` and be perfectly valid. However, my
new and improved understanding of hydrology definitions would say these are
separate and incompatible categories of rivers/streams. Page 6 of this EPA
document [1] has definitions that make these things clearer, maybe a
similar approach could be taken with the wiki.

> At present in OSM the tag to indicate an  intermittent flow that only
occurs in winter is intermittent=winter

> The proposal for ephemeral flow in autumn would be
ephemeral=autumn

> Combining these would give
> intermittent=winter
> ephemeral=autumn

> I would think that is easy enough to understand and matches the present
tagging scheme in use.

This is actually undocumented, and taginfo has no examples of seasons being
used as values for the `intermittent` key. With that said, I was also
suggesting that seasons might more appropriately be values for keys
describing "frequency/type of flow" like `intermittent` or `ephemeral`,
rather than having a separate `seasonal` tag, due to the ambiguity of
having more than one flow mode over the duration of a year. Something like
`intermittent:seasonal=` might also work. Maybe I'm missing a
proposal for seasonal values for `intermittent`?

The idea I'm proposing is that there may be a 'catch-all' key that
describes the 'type' of thing that `ephemeral` or `intermittent` are, and
to set `intermittent`, `ephemeral`, or otherwise (`perennial`?) values when
appropriate. What about `flow=ephemeral` or `flow=intermittent`? Then, if
you need to set more specifics, you could use `flow:ephemeral=winter`. This
also provides a convenient hint for what is being described: the flow type
of the stream.

> The intermittent tag already exists .. do you want to change it?

I think we're both considering changes to the `intermittent` tag as
potential options.

> And what if the stream has a seasonal flow in say winter and an ephemeral
flow possible in spring?
> For this proposal this would be tagged
> seasonal=winter
> ephemeral=spring

This is super confusing. Namely, the `seasonal` tag's documentation
indicates whether the feature is present, but in this case it seems to be
indicating that there is a 'full' flow. In other words, I would've assumed
you should tag it as `seasonal=winter;spring` and `ephemeral=spring`. This
becomes extra confusing when combined with the `intermittent` tag, for
which the wiki entry acknowledges there exist different interpretations for
the same tag combinations.

> The same can be said for roads. how stale is that data .. etc.

I'm just trying to get a better handle on the use case. How rapidly does
this tag become stale? Would data consumers use the tag? Would they instead
want a time series of observations, and if so, how frequently? It feels
like a tag that is science-ie, but I don't know whether, for example,
scientists would use it.

1.
https://www.epa.gov/sites/production/files/2015-03/documents/ephemeral_streams_report_final_508-kepner.pdf

Best,

Nick


On Fri, May 25, 2018 at 2:16 AM Warin <61sundow...@gmail.com> wrote:

> On 25/05/18 15:00, Nick Bolten wrote:
>
> If I understand this proposal right, the goal of this tag is to provide
> more specific information for the general likelihood of whether a water
> feature (only rivers?) exists: when it comes and goes every days.
>
> The tag provides mapper a way of tagging rivers and streams that is
> presently not available.
>
>
> This sounds like there are two pieces of information that are desirable to
> map:
> - What is the frequency of flow/presence?
>
> That will vary .. year to year and decade to decade ... to much change?
>
> - Does this frequency vary over seasons?
>
> This too will vary.
>
>
> These seem like questions that deserve separate tags, for flexibility, and
> could benefit from a 'subtag' approach. Let's say you want to describe a
> river that always has current in the spring and summer, is intermittent in
> the fall, and has no flow in the winter. This could look like:
>
> intermittent=yes;ephemeral;no
> intermittent:ephemeral=autumn
> intermittent:yes=winter
> intermittent:no=spring;summer
>
>
> Intermittent does not equal ephemeral.
>
> At present in OSM 

Re: [Tagging] RFC proposed water property key 'ephemeral '

[Christoph Hormann]

On Friday 25 May 2018, Warin wrote:
>
> Intermittent does not equal ephemeral.

So you have said repeatedly.

I know this is hard for native English speakers but you need to accept 
that tags in OSM do not generally mean what the English language terms 
they use mean.

intermittent=yes in OSM currently means quite precisely what the OSM 
wiki says it means:

"The intermittent=* key is used to indicate that a body of water does 
not permanently contain water."

This includes at least a few 100k features you would define as 
ephemeral.  You can't change that with a proposal.

There is a reason why such a broad and undifferentiated tag has become 
popular in OSM despite there being more differentiated concepts in 
existence:  Because more differentiation here is in many cases 
practically non-verifiable.  No matter if mappers observe on the ground 
or via images, the usual case is they see the waterbody in a dry state 
but see clear indications of recent water cover or water flow hence 
they can assume a non-permanent waterbody.  This is what you can 
currently indicate via intermittent=yes.

But requiring mappers to guess what kind of time pattern the change from 
dry to water cover follows does not work.  Offering this as an option 
in case mappers have more in depth knowledge is a good idea, i said 
that in the past.  But making it mandatory is bound to fail.

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

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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Warin]

On 25/05/18 15:00, Nick Bolten wrote:
If I understand this proposal right, the goal of this tag is to 
provide more specific information for the general likelihood of 
whether a water feature (only rivers?) exists: when it comes and goes 
every days.
The tag provides mapper a way of tagging rivers and streams that is 
presently not available.


This sounds like there are two pieces of information that are 
desirable to map:

- What is the frequency of flow/presence?

That will vary .. year to year and decade to decade ... to much change?

- Does this frequency vary over seasons?

This too will vary.


These seem like questions that deserve separate tags, for flexibility, 
and could benefit from a 'subtag' approach. Let's say you want to 
describe a river that always has current in the spring and summer, is 
intermittent in the fall, and has no flow in the winter. This could 
look like:


intermittent=yes;ephemeral;no
intermittent:ephemeral=autumn
intermittent:yes=winter
intermittent:no=spring;summer


Intermittent does not equal ephemeral.

At present in OSM the tag to indicate an  intermittent flow that only 
occurs in winter is

intermittent=winter

The proposal for ephemeral flow in autumn would be
ephemeral=autumn

Combining these would give
intermittent=winter
ephemeral=autumn

I would think that is easy enough to understand and matches the present 
tagging scheme in use.






The first tag declares the frequency, but doesn't specify when each 
tag applies. The other 3 describe how this frequency varies over 
seasons. The presence of more than one value for `intermittent` would 
be a hint for incremental mapping/QA: there should be one 
`intermittent:=` for every value in `intermittent`. 
Tagging a single water feature as always `ephemeral` would also be 
simple and get combined with the seasonal tag: 
`intermittent=ephemeral` `seasonal=`.

The intermittent tag already exists .. do you want to change it?

And what if the stream has a seasonal flow in say winter and an 
ephemeral flow possible in spring?

For this proposal this would be tagged
seasonal=winter
ephemeral=spring



I also have a follow-up about the use cases for this data. For 
example, for the cases I can imagine off the top of my head 
(scientific, humanitarian), it's valuable to know how stale the data 
is, how the person collecting it determined the value (memory, general 
impression as a local?), and ideally have a yearly report of flow (in 
some form or another), and so a wikidata key or external db may serve 
your use case better. Unfortunately, this raises a lot of hard 
questions about linking OSM and time series data that I don't think 
are solved, but it the discussion could be valuable in itself.


The same can be said for roads. how stale is that data .. etc.

The present tagging has no entry for ephemeral. None.
If you want more data .. such as flow rates .. then put it forward. It 
would need to include perennial flows, as well as seasonal, etc.

I don't think anyone wants that data in OSM ... yet.



Nick

On Mon, May 21, 2018 at 3:35 PM Warin <61sundow...@gmail.com 
> wrote:


Hi,

Following from the discussion on "Seasonal, intermittent, and
ephemeral
water tags" I have created this proposal.


Hopefully the definition is tight enough that it excludes
intermittent,
seasonal and any other thing that is not ephemeral.

I have also included a guide on determination so that mappers can see
how to determine if something is ephemeral.


So here it is ...

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


Is it clear? Do you understand it?


Would you use it? If so where?


Any thing else?





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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Nick Bolten]

If I understand this proposal right, the goal of this tag is to provide
more specific information for the general likelihood of whether a water
feature (only rivers?) exists: when it comes and goes every days.

This sounds like there are two pieces of information that are desirable to
map:
- What is the frequency of flow/presence?
- Does this frequency vary over seasons?

These seem like questions that deserve separate tags, for flexibility, and
could benefit from a 'subtag' approach. Let's say you want to describe a
river that always has current in the spring and summer, is intermittent in
the fall, and has no flow in the winter. This could look like:

intermittent=yes;ephemeral;no
intermittent:ephemeral=autumn
intermittent:yes=winter
intermittent:no=spring;summer

The first tag declares the frequency, but doesn't specify when each tag
applies. The other 3 describe how this frequency varies over seasons. The
presence of more than one value for `intermittent` would be a hint for
incremental mapping/QA: there should be one `intermittent:=`
for every value in `intermittent`. Tagging a single water feature as always
`ephemeral` would also be simple and get combined with the seasonal tag:
`intermittent=ephemeral` `seasonal=`.

I also have a follow-up about the use cases for this data. For example, for
the cases I can imagine off the top of my head (scientific, humanitarian),
it's valuable to know how stale the data is, how the person collecting it
determined the value (memory, general impression as a local?), and ideally
have a yearly report of flow (in some form or another), and so a wikidata
key or external db may serve your use case better. Unfortunately, this
raises a lot of hard questions about linking OSM and time series data that
I don't think are solved, but it the discussion could be valuable in itself.

Best,

Nick

On Mon, May 21, 2018 at 3:35 PM Warin <61sundow...@gmail.com> wrote:

> Hi,
>
> Following from the discussion on "Seasonal, intermittent, and ephemeral
> water tags" I have created this proposal.
>
>
> Hopefully the definition is tight enough that it excludes intermittent,
> seasonal and any other thing that is not ephemeral.
>
> I have also included a guide on determination so that mappers can see
> how to determine if something is ephemeral.
>
>
> So here it is ...
>
> https://wiki.openstreetmap.org/wiki/Proposed_features/ephemeral
>
>
> Is it clear? Do you understand it?
>
>
> Would you use it? If so where?
>
>
> Any thing else?
>
>
>
>
>
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Re: [Tagging] RFC proposed water property key 'ephemeral '

[osm.tagging]

That is actually pretty strongly dependant on El Nino:

http://www.bom.gov.au/climate/updates/articles/a008-el-nino-and-australia.shtml

The shift in rainfall away from the western Pacific, associated with El Niño, 
means that Australian rainfall is usually reduced through winter–spring, 
particularly across the eastern and northern parts of the continent. 

Nine of the ten driest winter–spring periods on record for eastern Australia 
occurred during El Niño years. 

vs. La Nina:

http://www.bom.gov.au/climate/updates/articles/a020.shtml

The increased rainfall and cloudiness in the western Pacific associated with La 
Niña usually means above-average winter–spring rainfall for Australia, 
particularly across the east and north. 

The six wettest winter–spring periods on record for eastern Australia occurred 
during La Niña years.

 

From: Graeme Fitzpatrick <graemefi...@gmail.com> 
Sent: Friday, 25 May 2018 14:12
To: Tag discussion, strategy and related tools <tagging@openstreetmap.org>
Subject: Re: [Tagging] RFC proposed water property key 'ephemeral '

 

 




Thanks

 

Graeme

 

On 25 May 2018 at 13:34, Warin <61sundow...@gmail.com 
<mailto:61sundow...@gmail.com> > wrote:

  
I'd not put a season on any of them .. too variable for me to determine a 
season. 

 

& that's the killer.

 

In Queensland, summer is supposed to be wet & winter dry, but something like 6 
years out of the last 12, we've had flood rains over winter?

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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Graeme Fitzpatrick]

Thanks

Graeme

On 25 May 2018 at 13:34, Warin <61sundow...@gmail.com> wrote:

>
> I'd not put a season on any of them .. too variable for me to determine a
> season.
>
>
& that's the killer.

In Queensland, summer is supposed to be wet & winter dry, but something
like 6 years out of the last 12, we've had flood rains over winter?
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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Warin]

To me the difference between ephemeral and intermittent is the duration 
of the water flow/presence.


To me Lake Eyre is intermittent.
The Fink Rv. is ephemeral.
The Cooper etc I don't know enough to say ephemeral.. so I'd use 
intermittent.
I'd not put a season on any of them .. too variable for me to determine 
a season.


On 25/05/18 13:11, Graeme Fitzpatrick wrote:
Not an OSM / mapping item as such, but on the subject of intermittent 
/ ephemeral waterways, I thought people may be interested in this?


http://www.abc.net.au/news/rural/programs/sa-country-hour/2018-05-24/lake-eyre-fills-water-tourists-feral-animals/9792352

So how do you map that lot? :-)

Thanks

Graeme



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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Graeme Fitzpatrick]

Not an OSM / mapping item as such, but on the subject of intermittent /
ephemeral waterways, I thought people may be interested in this?

http://www.abc.net.au/news/rural/programs/sa-country-hour/2018-05-24/lake-eyre-fills-water-tourists-feral-animals/9792352

So how do you map that lot? :-)

Thanks

Graeme
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Re: [Tagging] RFC proposed water property key 'ephemeral '

[osm.tagging]

The way I interpret it:

 

The default state (no tags) is:

 

water always flows

 

The seasonal, intermittent and ephemeral tags says

 

For these times, the explicit state is: the water always flows, is 
intermittent, or is ephemeral

For all other times, the default state is: the water never flows

 

Explicit state always overwrites default state.

 

The only thing left to specify now is the priority of the 3 keys. If two or 
more of them overlap in their explicit state for the same timeframe, which one 
has priority, or is it simply considered a tagging error?

 

From: Mateusz Konieczny <matkoni...@tutanota.com> 
Sent: Thursday, 24 May 2018 17:08
To: Tag discussion, strategy and related tools <tagging@openstreetmap.org>
Cc: 'Tag discussion, strategy and related tools' <tagging@openstreetmap.org>
Subject: Re: [Tagging] RFC proposed water property key 'ephemeral '

 




24. May 2018 06:39 by osm.tagg...@thorsten.engler.id.au 
<mailto:osm.tagg...@thorsten.engler.id.au> :

If I’ve understood it correctly, I would tag that as:

 

seasonal=winter,spring,autumn

ephemeral=summer

 

Yes, it would work. 

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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Mateusz Konieczny]

24. May 2018 06:39 by osm.tagg...@thorsten.engler.id.au 
:


>
> If I’ve understood it correctly, I would tag that as:
>
>  
>
> seasonal=winter,spring,autumn
>
> ephemeral=summer
>




Yes, it would work. 

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Re: [Tagging] RFC proposed water property key 'ephemeral '

[osm.tagging]

If I’ve understood it correctly, I would tag that as:

 

seasonal=winter,spring,autumn

ephemeral=summer

 

From: Mateusz Konieczny <matkoni...@tutanota.com> 
Sent: Thursday, 24 May 2018 16:28
To: Tag discussion, strategy and related tools <tagging@openstreetmap.org>
Cc: tagging@openstreetmap.org
Subject: Re: [Tagging] RFC proposed water property key 'ephemeral '

 




22. May 2018 22:53 by 61sundow...@gmail.com <mailto:61sundow...@gmail.com> :

Is that clear? 

 

Do how easiest that is

- flowing during winter, spring, autumn

- generally not flowing during summer but with possible ephemeral flows

 

should be tagged?

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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Mateusz Konieczny]

22. May 2018 22:53 by 61sundow...@gmail.com :


> Is that clear? 




Do how easiest that is

- flowing during winter, spring, autumn

- generally not flowing during summer but with possible ephemeral flows




should be tagged?

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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Warin]

On 23/05/18 07:25, Mateusz Konieczny wrote:




21. May 2018 22:34 by 61sundow...@gmail.com 
:


Hi,

Following from the discussion on "Seasonal, intermittent, and
ephemeral water tags" I have created this proposal.


Hopefully the definition is tight enough that it excludes
intermittent, seasonal and any other thing that is not ephemeral.

I have also included a guide on determination so that mappers can
see how to determine if something is ephemeral.


So here it is ...

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


Is it clear? Do you understand it?


No, "ephemeral=summer" is unclear -



It is a possible ephemeral flow (a flow of short duration) ... that can 
only occur in summer.


Similar to a tag seasonal=summer ... something that is seasonal that can 
only occur in summer.


I quote from the seasonal OSM wiki page
"describes exact season (if possible) when feature is present."

I'll put simillar on the proposed ephemeral page too, see below.



is it

for flow that is constant but ephemeral



An ephemeral flow is of short duration.
A constant flow would be there all the time ... so it could never be 
described as ephemeral.


---
The tagging text on the ephemeral page now reads
"If a season is specified it states the exact season (if possible) when 
the ephemeral can occur, during other seasons there would be no 
ephemeral flow.


For example, when tagged  ephemeral=summer the ephemeral flow can only 
take place in summer, thus the ephemeral flow is restricted to one season."


Is that clear?


Note that ephemeral=yes does not mean that a flow will occur every year.
It only says that any flow will be of short duration and will be dry 
most of the time.


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Re: [Tagging] RFC proposed water property key 'ephemeral '

[Mateusz Konieczny]

21. May 2018 22:34 by 61sundow...@gmail.com :


> Hi,
>
> Following from the discussion on "Seasonal, intermittent, and ephemeral water 
> tags" I have created this proposal.
>
>
> Hopefully the definition is tight enough that it excludes intermittent, 
> seasonal and any other thing that is not ephemeral.
>
> I have also included a guide on determination so that mappers can see how to 
> determine if something is ephemeral.
>
>
> So here it is ...
>
> https://wiki.openstreetmap.org/wiki/Proposed_features/ephemeral 
> 
>
>
> Is it clear? Do you understand it?
>
>




No, "ephemeral=summer" is unclear - is it 


for flow that is constant but ephemeral

during summer? Or water that is not present at all but flows ephemerally

only during summer? Or for both?

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