[Talk-GB] UK coastline data

Colin Smale colin.smale at xs4all.nl
Sat Jul 13 19:53:00 UTC 2019

On 2019-07-13 21:33, Tony Shield wrote:

> Hi 
> Personally think that High Water Mark and Low Water Mark are very relevant to people and to OSM. 
> Yeah - tides are a nuisance and can never be predicted with total accuracy and with Global Warming HWM and LWM will change over time. Then there are Highest and Lowest Astronomical Tides, and then tides which increase or decrease according to weather conditions (pressure and wind) (New Orleans tonight is a good example). There are probably a few others which I have forgotten.... 
> Knowing the inter-tidal area at Hunstanton is important, as are those in Morecambe Bay and the River Dee(North Wales/England)  where paths cross the area. 
> How many beaches are there on the Thames? and what is the inter-tidal ground like - sand, shingle, mud . . . .And what and where  is the access? These questions are what OSM is about. 
> The OS recognises this and on their maps marks the coastline/MHW with a dense line, but not on non-tidal waters. 
> OSM needs the equivalent of MLW - as far as I know its not defined (and I do not feel competent to define) - and I think that Borbus is on the good path.

What exactly do you mean by MLW not being defined? Do you mean that
there is not a robust definition of the concept? Or that it is difficult
to establish the exact line of MLW? 

Another reason to want MLW in OSM: The "Extent of the Realm" is *for the
most part* defined as MLWS. This is the limit of the jurisdiction of
normal (local) government. Beyond MLWS, the local council no longer has
any say - it's the UK laws of the sea, as applicable to territorial

I agree that Borbus is doing good things!
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk-gb/attachments/20190713/999183c7/attachment.html>

More information about the Talk-GB mailing list