[talk-ph] mangroves, tidal lands

Ed Garcia eppgarcia at gmail.com
Fri Jul 9 15:54:49 BST 2010


@maning,  I looked at your mangroves at Lian ... the coastline is actually
traversing the mangrove area, half on land and half on ocean, but it is
still being rendered as whole land.

I believe it is because you used the landuse:forest tag  while I used
natural:wetland tag as suggested by OSM for mangrove areas.

The natural:wetland does not render as a green patch when it is on the water
side of the coastline.

shall I use landuse:forest instead of natural:wetland instead?

On Fri, Jul 9, 2010 at 10:09 PM, <jeroen at bohol.ph> wrote:

>
> Can't find Mangrove here as a separate category. I believe normally
> coastlines are high-high waterlines. See this picture on my (site
> http://www.bohol.ph/picture206.html) for looks off a mangrove (near Loay,
> Bohol); this land will submerge a high tide. Picture can be used under CC-BY
> or CC-BY-SA if needed.
>
> Jeroen.
>
>
>
> Quoting maning sambale <emmanuel.sambale at gmail.com>:
>
>  A proposed  water_cover tagging:
>> http://wiki.openstreetmap.org/wiki/Proposed_features/Water_cover
>>
>> On Fri, Jul 9, 2010 at 3:39 PM, maning sambale
>> <emmanuel.sambale at gmail.com> wrote:
>>
>>> On Fri, Jul 9, 2010 at 11:15 AM, Ed Garcia <eppgarcia at gmail.com> wrote:
>>>
>>>> Can I have your opinion on this, guys?  it is about coastal mangrove
>>>> areas.
>>>> It is suggested, and I agree, to map mangrove areas as inland (inside
>>>> the
>>>> coastline).  But I encountered the mangrove areas at Alburquerque,
>>>>  Bohol and
>>>> the mangroves (seen on wms Lansat) are currently lying on the ocean
>>>> side.
>>>> The current coastline is along the actual edge of what is definitely the
>>>> actual land.  I have personally seen the coast myself when I was in the
>>>> Albuquerque area.
>>>>
>>>>
>>>> http://www.openstreetmap.org/?lat=9.6127&lon=123.954&zoom=14&layers=B000FTF
>>>>
>>>> Question:  Shall I move the coastline seaward so that the mangroves
>>>> would
>>>> apear inland?
>>>>
>>>
>>> IMO, no.  Some mangroves in Lian, Batangas are more on the sea side.
>>> Hence, I didn't move the the coastline.
>>>
>>> http://osm.org/go/4yfxfytF5-
>>>
>>> I've walked around these mangroves stands for two full days.
>>>
>>>  This would in a way state that mangroves (or tidelands) are
>>>> land and thereby also state that coastlines for tidal lands and  flats
>>>> are to
>>>> be drawn using the exposed areas during the lowest low tide (not just
>>>> the
>>>> mean tide as this will "cut" some mangrove areas in half).   Classic
>>>> case for
>>>> tidal flats are in Calatagan, where the low tide exposes an  additional
>>>> 150+m
>>>> of "land".
>>>>
>>>
>>> I have this similar case in Talim Bay (Lian, Batangas).  During low
>>> tides, the inter-tidal flats (locally known as tangkulan) are in
>>> hundreds of meters from the mean coast.
>>>
>>> http://farm2.static.flickr.com/1440/541589816_bf5bf812a2_b.jpg
>>>
>>>  Also, the above considers that some islands become "land" only on  low
>>>> tides.
>>>>
>>> The "if in doubt, map as land" mantra applies only if you're
>>> unfamiliar with the area.  For everything else, it's your call
>>> provided you have verified on the ground.
>>>
>>> I think we should map inter-tidal zones as lines (this needs to be
>>>  defined more)
>>>
>>>
>>>
>>>
>>>>
>>>>
>>>>
>>>> --
>>>> website administrator:
>>>> - www.waypoints.ph
>>>> - reeflife.eppgarcia.com
>>>>
>>>> PADI Divemaster #491048
>>>>
>>>> _______________________________________________
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>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> cheers,
>>> maning
>>> ------------------------------------------------------
>>> "Freedom is still the most radical idea of all" -N.Branden
>>> wiki: http://esambale.wikispaces.com/
>>> blog: http://epsg4253.wordpress.com/
>>> ------------------------------------------------------
>>>
>>>
>>
>>
>> --
>> cheers,
>> maning
>> ------------------------------------------------------
>> "Freedom is still the most radical idea of all" -N.Branden
>> wiki: http://esambale.wikispaces.com/
>> blog: http://epsg4253.wordpress.com/
>> ------------------------------------------------------
>>
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>>
>
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-- 
website administrator:
- www.waypoints.ph
- reeflife.eppgarcia.com

PADI Divemaster #491048
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