[Tagging] intermittent vs seasonal

Warin 61sundowner at gmail.com
Fri Oct 2 05:14:55 UTC 2015

On 1/10/2015 11:12 PM, Mateusz Konieczny wrote:
> On Thu, 1 Oct 2015 21:03:15 +1000
> Warin<61sundowner at gmail.com>  wrote:
>> On 1/10/2015 5:51 PM, Mateusz Konieczny wrote:
>>> According to what I found "intermittent" is not excluding regular
>>> changes - see for example "Intermittent streams flow seasonally in
>>> response to snowmelt and/or elevated groundwater tables resulting
>>> from increased periods of precipitation and/or decreased
>>> evapotranspiration." from "Temporary streams" by Margaret Palmer,
>> Meaning the streams ONLY flow sometimes and ONLY when there is snow
>> melt /rain fall ..
>> So the two things combine to say ..
>> if there is snow melt or rainfall
>> then there MIGHT be water in the stream.
>> To me that is not seasonal..
> I am not sure how it is a problem, because it is definition of
> intermittent waterway.

At the moment the 'intermittent' wiki says;

In Description:/Indicates that waterway or water body is intermittent (seasonal) /

In Key:intermittent:/Or that a water body (lake) disappears seasonally./

The use of seasonal here limits it to things that have a yearly cycle.

I would rather remove the 'seasonal' references .. something like

In Description:/Indicates that waterway or water body is intermittent./  

One could add the word/irregular/  or/random/  in brackets if helpfull?

In Key:intermittent:/The tag //*intermittent*=yes//is used to indicate that a waterway (river, stream, etc.) or a water 
body (lake) has random dry and wet periods./

Any 'season' things should be addressed by the key:seasonal.

The original proposal had no mention of seasonal
perhaps because the seasonal key was introduced later.. and now people want to advertise the key seasonal, not a bad thing if done correctly.

>> unless you can say that the rain and
>> snow only falls in given parts of the year and at no other time?
> That is one of cases where waterway is intermittent and seasonal.

Humm ... I'm thinking on it. It is random but only in certain times of the year. OK.

But intermittent does not imply seasonal to me and at least some others.

>> Given the weather does not conform that well to the 'season's .. I'd
>> be more inclined to leave off the seasonal tag.
> It depends on location.

NO. It should depend on the features characteristic. But I think we agree here.

>>> There is nothing wrong with adding both intermittent=yes and
>>> seasonal=yes.
>> intermittent= irregular = not regular.
>> seasonal= regular.
> According to your second mail one of synonyms of intermittent is also
> "periodic". It is not 1:1 mapping, especially as "intermittent"
> appears to have a defined meaning in hydrology.

This may be a case of "common use" definition being different to "specialist use" definition.
I have a few of those! Very annoying to the 'commoner'! (e.g. me and hydrology)

>> For me I would simply tag something that is irregular
>> intermittent=yes, and leave out the seasonal.
>> If it 'typically' flows seasonally then don't use intermittent, use
>> seasonal=yes(winter,summer etc)!
> Why not use both in cases of waterways that are not permanently
> filled with water? To make it harder to use data?

If it is random ONLY .. then only use intermittent.
If it is seasonal ONLY then only use seasonal.

This makes the data specific, correct and better as each describes what happens,
seasonal for yearly repeating things, intermittent for things that are random.

Where it is both seasonal and during that season random then .. both, but only then.

>> Using your above snow melt example .. does snow not fall out of
>> season occasionally?
> Depends on location.

Further thinking on this .. 'we' only map the typical .. not the exceptions. So my thoughts there are out of line!

>>>    Also, there is no good reason to break data consumers by
>>> removing popular and correct intermittent=yes and adding a new tag
>>> (seasonal=yes).
>> seasonal is an existing tag. And should be used to mark things that
>> are regular on a yearly scale.
> I am not protesting adding seasonal=yes, I am protesting removing
> correct intermittent=yes tags.

I am not removing tags .. but getting a good wiki definition of them.

Prior to April 2014 the wiki for intermittent had no reference to 'seasonal' in its description.

>> The intermittent tag should NOT be used for things that are seasonal.
> And it should be used for things that are both seasonal and
> intermittent.
>> We should tag the truth. That is what the consumers expect.
> Yes. I am also not aware about anybody disputing this.
>> Note that this came about because someone took intermittent to mean
>> it happened on a regular yearly basis.. and that is wrong.
> Yes. This is clearly wrong.

And 'we' now have on the intermittent wiki the statement

"/In case of waterways or lakes becoming dry on specific times of year one 
may add also //seasonal <http://wiki.openstreetmap.org/wiki/Key:seasonal>=yes 

I would say

"/In case of waterways or lakes becoming dry on specific times of year the 
key" //seasonal <http://wiki.openstreetmap.org/wiki/Key:seasonal>=* 
<http://wiki.openstreetmap.org/w/index.php?title=Tag:seasonal%3Dyes&action=edit&redlink=1>//. should be used alone, not with the key:intermittent.////Example:////waterway=stream////name=sample////seasonal=summer//////The stream "sample" only flows in the summer season./"

And, if you want further on when to use both ? Probably best !!!

"/In the case of a waterway or lake that may randomly have water but only 
in a certain time of the year then use both seasonal=* and 
intermittent=yes.////Example:////waterway=lake////name=simple////seasonal=spring////intermittent=yes//////The lake "simple" only has water randomly during the spring season./"

I think this should be in a separate section ...

The seasonal wiki page is also deceptive on the use of the key:intermittent. I would think similar statements/corrections should be made there.
The problem is if the definitions/use change on one are not reflected on the other page.

Looking at the wider wiki too !


suggests replacement of

waterway=wadi and waterway=drystream


waterway=river or stream



The wiki for

waterway=wadi  suggests (presently) using intermittent for seasonal!

waterway=drystream ...errr arr yes.. also suggests using intermittent for seasonal.

I do think the use of key:seasonal for seasonal things makes a lot more sense than using the key:intermittent!

So those wiki pages too need better statements/correction.

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