Proposal:Shelf

this proposal has been removed from the proposal page as it is badly explained (this is an english-language wiki) and appears to overlap with other proposed or existing tags

I would like to propose this new feature to tag some lagoon area that are [below] sea level just when the tide is high and [are dry when the tide is low].

That area could be rendered as a lighter blue with some grass icon overlayed.

I'm using this to tag some area of the Venice (Italy) lagoon

--EdoM (Parliamone) 10:28, 7 June 2007 (BST)

You can find a barena description (italian only) here

Opinion

Hi! we are working on a general proposal for boating related information. This IMHO should go in the Tidal section. The reference to Tidal is basically associated with water level (it makes a big difference to decide whether you can sail in a place and when). Probably the safest way to reach a derived information for Shelves would be having altitude information recorded on the ground and then a Tidal area reporting the variation in feet or meter that is expected. I gather shelves in italian cartography are anyway identified by using a an average seasonal tidal value, are they? Tidal areas are extremely relevant in oceanic coastal areas (and to define rivers' depth in their tidal regions --Bèrto 'd Sèra 12:58, 7 June 2007 (BST)

In Venice these areas are named barena. Every 6 hours barena emerge from the lagoon water and after another 6 hours the are submerged.. This area is absolutely not navigable at all. Some canal are excavated to permit navigation, but only with some type of boats. Nobody will sail barenas..

I'm Potlaching (?) so you can take a look at the Yahoo aerial imagery if you like. Find out Venice, move to the west reaching the land and the slide south. You can find some dark green areas. That are barenas--EdoM (Parliamone) 13:15, 7 June 2007 (BST)

I know, I lived in Venice for a few years :) It doesn't matter whether they are navigable or not (most marginal tidal areas arent', you need an excursion of at least 1-1,5 meters to allow even the most shallow dutch plateboden venture in them). This should be definable by entering an average tidal excursion (in Venice 1,5 meters in barenas would be a major case of acqua alta in the city, if I recall correctly, so you can hardly expect that). At that point renderers could show in different flavors non-navigable barenas and navigable tidal areas. These areas are important because they are often used to moor boats in what is called a mud berth. You have enough water to get there, then water goes away, your boat sits on the mud (no keels here, flat bottoms only!!) and you can have a walk on the beach. Very popular in Holland, although I can't really imagine doing that in barenas :) The main problem is finding a way to define things that will not strongly depart from cartography standards, but will also let boaters collect and enter information in a standardized way --Bèrto 'd Sèra 13:55, 7 June 2007 (BST)

• Perhaps this would be more understandable to most contributors and broadly useful as natural=tidal_flat or is there something specific I've missed? Just a thought. MikeCollinson 09:20, 11 June 2007 (BST)

Is this similar to the Proposed features/Water cover tags? Ojw 12:31, 23 September 2007 (BST)

this proposal has been removed from the proposal page as it is badly explained (this is an english-language wiki) and appears to overlap with other proposed or existing tags