[OSM-newbies] mapping islands of a salt flat

[Alexandros Papadopoulos]

On 24 November 2011 13:38, Craig Wallace <craigw84 at fastmail.fm> wrote:
> On 24/11/2011 15:33, Alexandros Papadopoulos wrote:
>>
>> Hello.
>>
>> I am mapping the islands of the Salar de Uyuni
>> (http://osm.org/go/NK_7Jv--) as I found it particularly annoying they
>> were not on the map when I needed this information.
>>
>> The one island that *was* already mapped
>> (http://www.openstreetmap.org/browse/way/43540410) was tagged with
>> natural=land which seems to be deprecated.
>>
>> For this case (a salt flat), I have been using natural=coastline and
>> place=island/islet. Is this OK?
>
> No - islands within the sea should be tagged with natural=coastline, but not
> islands within inland water, eg lakes/ponds/rivers.
> That Salar de Uyuni is tagged as natural=water, so it counts as inland
> water, and is equivalent to a lake or pond.
>
> Islands in inland water need to mapped with multipolygon relations. ie map
> the island as an area, and add it to a multipolygon relation with role
> "inner", and add the outline of the lake to the relation with role "outer".
> I see that Isla Incahuasi is already mapped with a multipolygon relation, so
> you can add all of the other islands to the same relation, with role inner
> for each.
>
> There is no need to tag the islands with natural=land. It is more useful to
> tag what is actually there. eg if the island is covered with trees then tag
> it with natural=wood, or if its a beach tag it as natural=beach etc.

Thanks Craig.

So to sum up:

1. Mark the island as an area.
2. Add any useful designations (natural=beach etc)
3. Add to multipolygon relation.

I have attempted to do just that for the 20odd islands I can see on
Bing aerial photography, hope I did the right thing.

Cheers

Alex