[Tagging] Feature Proposal - RFC - Ephemeral a water property key.

Warin 61sundowner at gmail.com
Thu Dec 13 00:42:56 UTC 2018

I qutoe for the proposal page
On 13/12/18 10:44, Joseph Eisenberg wrote:
> These comments on the proposal are still valid issues: 
Changes have been made  to address them.
Should these changes be duplicated on the comments page too??
> “‘at least 90% of the time’ is impossible to be determined by mappers 
> and is an arbritrary value. 
Present page reads
/The majority of the time, say at least 90% of the time, the water is 
not present./

An attempt to define 'majority' for those that think the term is not 
objective. Possibly the term 'majority' should be further developed .. 
probably 'vast majority' would be better. If you like it is the reverse 
of  'seldom' .. that could be 'defined' as 'say no more that 10% of the 
time'??? Humm I may change to 'seldom'.

When you say 'impossible to determine' .. you mean that no one ever can 
determine it? Yet the term exists and is in use so people can determine it.
If you mean that a mapper lacks the information, then they should not 
use the tag!!! Those mappers who know that it is ephemeral should not be 
denied the use of the tag because some, possibly most, lack that 

> “ephemeral=dry_season has no obvious meaning (is it tagging that 
> waterways is ephemeral during dry season? Or is it tagging that 
> waterway is ephemeral and may flow only during dry season”

The page gives an example
seldom be here and only for a short duration and only in winter. It 
would be rare to have more than one water presence during the season./

Substitute dry season for winter and you have an answer?

The page then goes on to say
exact season (if possible) when a feature can be ephemeral./
/Implies //ephemeral 
that season. Note safest to use //ephemeral 
this avoids difficulties of determining the season. /
> “the proposed values do not seem right (ephemeral=dry_season is 
> certainly impossible)”

The page states
/Note that seasonal=dry_season is in use (even if by error or maybe it 
is in use on non-water features e.g. roads, some 2,900 uses of it), so 
it has not been excluded here as there might, just possibly, be one of 
them out in the real world. There is also the possibility that the 
'dry_season' is a relative term and it could have random rain?/
Maybe a definition of dry_season is that it does not rain at all .. yet 
where is that documented that no rain can fall? Another definition of 
dry_season could be that rain seldom falls.

> Perhaps limiting the initial proposal to ephemeral=yes would be helpful.
> I would still like to see discussion of the cut-off between regular 
> intermittent=yes and ephemeral=yes. 

The page gives some indications of the differences.
As the page is not that to define what intermittent is perhaps that 
discussion should take place on the intermittent page where it belongs?

/This infrequent occurrence and short duration signifies the difference 
between this tag and //intermittent 

	/Water may be here in winter but not all the time. There may be more 
than one water presence during the season. /


/Water seldom here and only for a short duration and only in winter. It 
would be rare to have more than one water presence during the season. /

> Perhaps a simpler statement like “an ephemeral water feature contains 
> water less than once a year, on average” would be clearer?

Thanks for that ... but ..
Lacks the 'short duration' that is the source of the word 'ephemeral'.
Ummm .. the difficulty is defining a 'short duration' in objective terms?

The other small point is 'contains' ..

“an ephemeral feature has the presence of water for a short duration and 
less than once a year, on average”
But that still does not say what a 'short duration' is. Difficult. May 
be 'less that a week' ???

> On Thu, Dec 13, 2018 at 8:15 AM Warin <61sundowner at gmail.com 
> <mailto:61sundowner at gmail.com>> wrote:
>     Hi
>     I have reworked the ephemeral proposal.
>     This now demonstrates;
>     the difference between intermittent and seasonal - some want to
>     combine
>     them into one and see the ephemeral key as just another
>     intermittent/seasonal thing so they vote no.
>     that ephemeral applies to more that just streams - some want it as
>     a sub
>     key to streams .. that is not possible if it applies to other things,
>     these people too vote no.
>     It now draws on the seasonal page to demonstrate the use of the
>     seasonal
>     values.
>     I see this key being used by the experienced local who can draw on
>     local
>     knowledge.
>     The arm chair satellite mapper will have to stick with
>     intermittent as
>     they will not be able to determine if seasonal nor ephemeral
>     apply, they
>     may not even be able to determine intermittent.
>     I hope this proposal page is now somewhat clearer?
>     https://wiki.openstreetmap.org/wiki/Proposed_features/ephemeral
>     ---------------------------
>     I may do a dairy entry on seasonal, intermittent and ephemeral.
>     Looks to
>     me like a lot of confusion probably promoted by the use of
>     intermittent
>     everywhere.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/tagging/attachments/20181213/89c53c20/attachment-0001.html>

More information about the Tagging mailing list