[talk-ph] areas of mangrove

[David Groom]

There are two different approaches used in mapping mangrove  areas in OSM

1)  Treat the boundary of the mangrove and the openwater sea as the 
coastline, and then map the area between that line and the "dry" land as 
wetland.  This means that the wetland symbols are rendered over the 
white colour of the land, and that at zoom levels 12 and lower the 
mangrove areas simply get shown as white, with the sea outside them.

2)  Treat the boundary of the mangrove and the "dry" land as the 
coastline, and then map the area between that line and the openwater sea 
as wetland.  This means that the wetland symbols are rendered over the 
blue colour of the sea, and that at zoom levels 12 and lower the 
mangrove areas simply get shown as blue sea.

Early today I added some mangrove areas and followed approach 2 because 
the coastline had been accurately mapped along the mangrove / dry land 
boundary, as so I simply added the mangrove area outside this, as it 
seemed the existing mapper had cleary thought the coastline should be at 
the dry land boundary.

However at  http://www.openstreetmap.org/#map=14/9.7497/125.6105 both 
these approaches have been used.  Approach 1  has been used for Lamagon 
Island, where the boundary of the mangrove area and the sea is tagged as 
coastline.  But Approach 2 has been used for the island immeditately 
south, where the boundary of the dry land is tagged as coastline.

On further investigation I see at 
http://www.openstreetmap.org/#map=14/9.7003/125.6415  that Approach 1 
has been used.

Has this issue been discussued before within the Philippine OSM 
community, with any recommended way of mapping mangrove areas being 
decided upon?

Regards
David