[Tagging] Coastlines and structures

[David Groom]

> ----- Original Message ----- 
> From: "Peter Childs" <pchilds at bcs.org>
> To: "Tag discussion, strategy and related tools" 
> <tagging at openstreetmap.org>
> Sent: Tuesday, December 08, 2009 3:21 PM
> Subject: Re: [Tagging] Coastlines and structures
>
>
>
> 2009/12/8 David Fawcett <david.fawcett at gmail.com>:
>> I have a few questions on best/standard practices for delineating
>> coastlines and tagging the features.
>>
>> 1. Is there general agreement on where the primary water body ends
>> and a contributing river starts?
>
> Last I heard it was a judgement call. Dependant upon Tidal Water end,
> Bridges, Current, Man made Structures etc. and also when people
> generally stopped calling it the "Sea" and started calling it the
> "River",
>
Basically that how I approach it.  As I've argued before simply basing it on 
is it tidal is for me too simplistic.

The River Thames  through London is Tidal, but ask any Londoner do you live 
on the coast or on a river and I'd guess well over 99% would say they did 
not live on the coast.


>>
>> I am thinking of an area where the PGS data cuts a large bay/estuary.
>> The line was defined by a bridge crossing the water, my assumption is
>> that this line was chosen because the bridge was incorrectly
>> interpreted as land. Ocean-going ships pass under this bridge to the
>> water behind it.
>>
>> 2. Coastline delineation around structures. Based on reading old
>> posts and wiki pages, it seems like the general practice for solid
>> structures, like harbor walls and jettys is that the coastline follows
>> the edge of these features and then an additional area is defined to
>> delineate the structure itself.
>>
>> For piers, constructed on pilings where water flows through the
>> pilings, should the coastline follow the solid shoreline, or should it
>> follow the outline of the pier? I guess, is coastline determined
>> based on navigability or by the ability of water to flow?
>>
>> Any input would be great.
>>
>
> Its the Flow of Water that counts. so the coastline does not include
> any piers bridges that over hang.
>
> This is what I understood after the last thread on this on Talk.
>

Again I agree, if there is water under a strucure then that structure is 
above the sea, and therefore the coastline is unaffected by the structure

David
>
> Peter
>