[Tagging] Seasonal, intermittent, and ephemeral water tags

Warin 61sundowner at gmail.com
Sat May 26 07:02:52 UTC 2018


On 21/05/18 07:57, Warin wrote:
> On 20/05/18 18:33, Mateusz Konieczny wrote:
>> 19. May 2018 04:33 by 61sundowner at gmail.com 
>> <mailto:61sundowner at gmail.com>:
>>
>>     The intermittent tag continues to be confused with seasonal.
>>
>>     Possibly this is because some want to use it to indicate that a
>>     follow is both seasonal and intermittent?
>>
>>
>> At least in my case it was like this:
>>
>>
>> - I discovered intermittent tag
>>
>> - later I encountered someone claiming that seasonal water flow
>>
>>   should be tagged with seasonal tag
>>
>> - I checked intermittent definition in some sources and found no
>>
>>   confirmation that "intermittent" excludes cyclic changes
>>


If 'intermittent' is taken as the same as seasonal then why have both keys?
To me they are not the same.
Take for example Lake Eyre in Australia. It is a salt lake that is dry 
most of the time. It does not fill yearly, so it does not follow a 
yearly cycle.
Nor does it only follow a local season .. or even a remote season.
The water usually comes from Queensland .. some 1,000s of km away.
Once it fills, water remains for quite some time .. say 2 months.
Historically it used to have significant water in it (not necessarily 
full) about every 10 years.
Now it looks to have significant water in it (not necessarily full) 
about every 5 years.

So it cannot be tagged seasonal .. as it follows no yearly cycle.
It cannot be described as ephemeral as it has a long duration.

The locals say it is intermittent as do the officials.  That is how it 
is tagged in OSM.

--------------------------------
In my case:

I think we all have been dealing with seasonal things since birth - so 
should understand its definition.

I have been dealing with 'intermittent' things for most of my 
professional life. So have some understanding of what that means.

Ephemeral is a new term for me.  I have been looking at the various uses 
of the word and various definitions. I was prompted by the thoughts of 
another mapper.

--------------------
My take  for water bodies:

Perennial: I expect to find water here at any time. Exceptions: drought

Seasonal: I expect to find water here on a yearly cycle, usually for 
months. Exceptions: drought

Intermittent: I don't expect to find water here. Exceptions: heavy 
rainfall or snow melt. The water could be here for some time .. up to 2 
months.

Ephemeral: I don't expect to find water here. Exceptions: heavy rainfall 
or snow melt. The water can only be here for a short time .. less than a 
week, usually a day or less.






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