Proposed features/ephemeral

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"ephemeral"
Status: Voting (under way)
Proposed by: Warin61
Tagging: ephemeral=no/yes/spring/summer/autumn/winter/dry_season/wet_season
Applies to: node, way, area, relation
Definition: Indicates water presence is of short duration.
Rendered as: vertical dashed blue
Drafted on: 2018-05-21
RFC start: 2018-05-22

Proposal

Add the property key [W] ‘ephemeral’ to indicate the very short duration of water in some water features.

The syntax follows the other property keys syntax.


Definition

A property key for water that is only present for short duration. ‘Short duration’ is typically less than 1 day for each water presence. The maximum duration of water presence would be 7 days. The majority of the time, at least 90% of the time, the water is not present.


Determination guide

Determination of a water feature as ephemeral requires knowledge of other local ephemeral waterways (determination by proximity), historical flow/presence (determination by features objective data) and/or rainfall patterns (determination by local objective data).

Where a water feature feeds into another ephemeral water feature that would indicate that this water feature too is ephemeral.

Where a water feature is near an ephemeral water feature that is in the same type of climate that would indicate that this water feature too is ephemeral.

Where the historical flow/presence of a water feature is ephemeral that would indicate that this water feature is ephemeral.

Where a water feature feeds resides in a climatic area of sporadic rainfall (example; no rain for years and then a few years rainfall all in one or two days) that would indicate that this water feature is ephemeral.

If it cannot be determined then do not add this tag.


If you are certain the the flow/presence is ephemeral and on occurs in a certain season or seasons then tag the season/s as a value in the ephemeral key.

Rationale

A lot of streams, rivers and possibly lakes in deserts are [W] ‘ephemeral’.

Examples

Way: Todd River (208044858) [W] Todd_River Todd River1.jpg |Todd River 31March88.jpg

Note the bridge viewable in the first photo gives some relativity to the water shown in the second photo.


Way: Tsauchab (380562360) [W] Tsauchab River

Tagging

ephemeral=no/yes/spring/summer/autumn/winter/dry_season/wet_season The default value is no.

The values are the same as seasonal=*. 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/s is/are restricted to one season. For more than one season use the ; separator for example ephemeral=spring;summer would mean that the ephemeral flow/s is/are restricted to the two seasons of spring and summer.

Applies to

Water features. In the OSM data base there is a wetland with the value ephemeral.

Are there any other features that have this short duration?

Rendering

Proposed rendering for ephemeral water features: a vertical line of alternating blue dashes.


Features/Pages affected

Add as a possible property key to water features pages such as streams, rivers, lakes.

Tagging errors

If tagged seasonal=winter and ephemeral=winter then is the water present during winter most of the time (seasonal=winter suggest this) or is the water present only for short durations during winter (ephemeral=winter suggest this). This is a conflict of tags.

Default or addition of intermittent=yes

There is some suggestion that the key intermittent=* should be manually added to all ephemeral entries. This places the work load on the mappers, if a default of intermittent=yes is stipulated for ephemeral entries then the work load transfers from manual entry by mappers to data consumers who may automate the process. There are 2 options below, vote for the one that you think is best, votes against will be ignored on the tally but you may comment to express your view.

Voting on this will be which ever option has the maximum yes vote. If you don't vote for the addition of the ephemeral key then you should not vote for any option of the key.

Voting on the key ephemeral STOPPED DUE TO REMOVAL OF MATERIAL! Will restart after corrections

Start date was 17-7-2018, end date after 31-7-2018 (probably a fair way after).

Instructions for voting
  • Log in to the wiki if you are not already logged in.
  • Scroll down to voting and click 'Edit source'. Copy and paste the appropriate code from this table on its own line at the bottom of the text area:
I approve this proposal yes {{vote|yes}} --~~~~
I oppose this proposal no {{vote|no}} reason --~~~~
Replace reason with your reason(s) for voting no.
I abstain from voting but have comments abstain {{vote|abstain}} comments --~~~~
If you want don't want to vote but have comments. Replace comments with your comments.

Note: The ~~~~ automatically inserts your name and the current date.


  • I approve this proposal I approve this proposal. Warin61 (talk) 22:24, 16 July 2018 (UTC)
  • I oppose this proposal I oppose this proposal. We should be using a generalisation of stream=* instead of this --Adavidson (talk) 09:34, 17 July 2018 (UTC)
  • I oppose this proposal I oppose this proposal. "at least 90% of the time" is impossible to be determined by mapped and is a completely arbritrary value. 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? It requires careful reading of documentation to answer this question). --Mateusz Konieczny (talk) 14:30, 17 July 2018 (UTC)
  • I oppose this proposal I oppose this proposal. I am against this proposal because the seasonal=* tag already exists with the same idea. What needs to happen is that intermittent and seasonal tags need to be combined into one tag of intermittent. Just like building=yes, intermittent=yes would be the default choice if you do not have information about seasonal or ephemeral conditions of the intermittent body of water or cannot make a guess. Both the harmonized ideas of season and the ephemeral values could replace the yes value, if known. --Dr Kludge 08:30, 28 July 2018 (UTC)
  • I abstain from voting but have comments I have comments but abstain from voting on this proposal. Elaborating on intermittent water bodies is a good idea, but the proposed values do not seem right (ephemeral=dry_season is certainly impossible), and I do not see why we shouldn't use intermittent=* for new values directly (e.g. intermittent=episodic/wet_season/snowmelt/etc.). I don't vote "no" because I am not a desert expert. However, I'd like to point out that ephemeric waterways also exist in alpine regions where some brooks carry superficial water once every couple of years during heavy rainfalls. Maybe "wet_season" is not strong enough to express these rare conditions. --Fkv (talk) 19:39, 17 July 2018 (UTC)
  • I abstain from voting but have comments I have comments but abstain from voting on this proposal. The hydrography distinct in: perennial,seasonal,ephemeral and intermittent (waterway) streams. The use "ephemeral=yes" for waterflow only after heavy rainfall or snowmelt makes sense. But with some other proposed values like "wet_season" I have a problem. --Schröcker (talk) 15:06, 30 July 2018 (UTC)

Optional voting on a default of intermittent=yes for the key ephemeral STOPPED DUE TO REMOVAL OF MATERIAL! Will restart after corrections

Vote here as to if a default value of intermittent=yes should be stipulated with the key ephemeral.

Instructions for voting
  • Log in to the wiki if you are not already logged in.
  • Scroll down to voting and click 'Edit source'. Copy and paste the appropriate code from this table on its own line at the bottom of the text area:
I approve this proposal yes {{vote|yes}} --~~~~
I oppose this proposal no {{vote|no}} reason --~~~~
Replace reason with your reason(s) for voting no.
I abstain from voting but have comments abstain {{vote|abstain}} comments --~~~~
If you want don't want to vote but have comments. Replace comments with your comments.

Note: The ~~~~ automatically inserts your name and the current date.


  • I approve this proposal I approve this proposal. Warin61 (talk) 22:24, 16 July 2018 (UTC)
  • I abstain from voting but have comments I have comments but abstain from voting on this proposal. Let's be realistic; the chance that OSM Carto is going to start rendering anything other than intermittent=yes in the near future is small. Better to just think of it as another example of highway=bus_stop.
  • I oppose this proposal I oppose this proposal. intermittent=yes should be still added. Adding just ephemeral=wet_season is in my opinion like tagging isced:level=* without tagging amenity=school --Mateusz Konieczny (talk) 14:27, 17 July 2018 (UTC)
  • I oppose this proposal I oppose this proposal. intermittent=yes provides the needed information. The values for intermittent should be expanded as noted in the voting above. --Dr Kludge (talk) 19:43, 29 July 2018 (UTC)
  • I approve this proposal I approve this proposal. Redundant tags should be avoided wherever feasible. --Fkv (talk) 18:20, 17 July 2018 (UTC)
  • I abstain from voting but have comments I have comments but abstain from voting on this proposal. We are using "intermittent" for streams in a wrong way (meaning). See the discussion page on Key:intermittent. --Schröcker (talk) 15:06, 30 July 2018 (UTC)