[Tagging] Coastal beach definition for mapping.

[Warin]

On 03/04/18 23:22, Martin Koppenhoefer wrote:
>
>
> sent from a phone
>
> On 2. Apr 2018, at 23:40, Graeme Fitzpatrick <graemefitz1 at gmail.com 
> <mailto:graemefitz1 at gmail.com>> wrote:
>
>> Should it continue more or less straight, following the line of the 
>> beach, across the mouth of the estuary; or should it follow the 
>> estuary / river bank for an undetermined distance inland?
>
>
> the coastline should represent the limit of the sea, in case of a 
> river flowing in, people look at the level of salt in the water and 
> whether the level of the river is influenced by tides (afaik), for 
> example here you can see a coastline at a “river”:
>
> https://www.openstreetmap.org/way/88960837#map=9/53.6926/9.3947

River flows can be extremely different from one season to the next in 
some parts of the world.
Consider the tropics where the major seasons are described as 'wet' and 
'dry', river levels can change by 5 meters between the seasons.

In other places the tide can influence river levels for many kilometres 
inland.

In both those cases the salt levels will vary from one extreme to another.

Possibly best to take the minimum intrusion of the sea into the river? 
Maybe not for some though - the rate of flow will have fresh water going 
out into what most would call the sea!

Where this detail is unknown then Graeme's approach of a straight line 
across the mouth of the river can be used to minimise work and signify 
the lack of information or the conflict for the area.
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