[Tagging] Tidal inlets / creeks

[john at jfeldredge.com]

It seems to me that you would need to map a series of depth contours, not simply mark channels as navigable or not navigable, as different craft will require different depths of water.  Also, this information will need to be updated frequently, as some shoals can shift position with every storm.

-------Original Email-------
Subject :Re: [Tagging] Tidal inlets / creeks
From  :mailto:charlie at cferrero.net
Date  :Tue Jan 18 10:56:16 America/Chicago 2011


Malcolm Herring (malcolm.herring at btinternet.com) wrote:

> On 18/01/2011 12:44, charlie at cferrero.net wrote:
>>
>> It would be nice to be able to map the tidal waterways that run in
>> between the mangroves and saltmarshes - particularly the manmade ones
>> that have been explicitly cleared to allow marine vessels. Unfortunately
>> I can't see any way of tagging a waterway that does not imply
>> freshwater. Ideally we'd have a waterway=tidal_creek or something like
>> that but this doesn't seem to be in use at all.
>>
> A way tagged natural=coastline should follow the local mean *high*  
> water level so that all tidal areas will be on the wet side of the  
> way. Any tidal areas (wetlands of all types, beaches, mud, etc) can  
> be mapped as closed polygon ways that enclose areas above the local  
> mean *low* water level. These areas will be rendered at the higher  
> zoom levels. Navigable channels that exist between these areas will  
> then have been left as non-tidal (i.e. always wet)
>>
Thanks.  I understand what you're suggesting, and I was probably a bit  
misleading in my original email.  The problem is how to differentiate  
between sub-low-water level areas that are 2m deep, and the (often  
man-made) channels that are sufficiently deep to allow navigation.

-- 
Charlie


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John F. Eldredge -- john at jfeldredge.com
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