[talk-au] mapping marsh at the edge of a bay

info at 4x4falcon.com info at 4x4falcon.com
Wed Dec 22 03:46:10 GMT 2010


>> http://www.openstreetmap.org/?lat=-34.03275&lon=151.13694&zoom=17&layers=M
>>
>> Along the edge of the bay/water there is
>>
>> land--> | <--trees in water--> | <-- water
>>  A                  B                C
>>
>> In the changeset http://www.openstreetmap.org/browse/changeset/6723657
>> I moved the edge of the water (which did cover both B and C) in
>> towards the center of the bay, and made section B marsh. But I'm not
>> sure if that was the right thing to do. Maybe it would be better if
>> the natural=bay/water area included both B and C, and the boundary for
>> B just laid on top of the B/C area. But since we use a proper
>> mulitpolygon for doughnut geometries, just dumping B on top wouldn't
>> look so nice....
>>
>> What if B was tagged as marsh, C as water, and then add B and C to a
>> multipolygon tagged as the bay? Or is how its mapped currently how it
>> should be? Any thoughts?
>
> Interesting question - to be honest I'm finding it a bit hard to
> understand your exact situation ("moved the edge of the water...in
> towards the centre of the bay"?) But I don't know for sure what the
> coastline should represent, so I'd be interested to hear opinions on
> this too.
>
> I think a similar example is here:
>
> http://www.openstreetmap.org/edit?editor=potlatch2&lat=-38.298693&lon=145.199326&zoom=18
>
> Steve

I usually map these as in the second example, ie coastline along the water
to marsh/mangrove boundary then separate area for the marsh/mangroves.

I'd also suggest that the treed area should be natural=wetland
wetland=mangrove rather than natural=marsh.

Cheers
Ross






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