[OSM-talk] New tool in Potlatch 2 for areas that share a way

[Frederik Ramm]

Hi,

On 01/31/11 02:27, Steve Bennett wrote:
> Does that apply for coastlines as well? Or do coastlines not even need
> the multipolygon?

Coastlines do not use multipolygons. But if you have an area that is 
bounded by coastline - say, a beach area - then you can create a 
multipolygon for the beach. In the simplest case, the beach multipolygon 
would consist of exactly two ways, one being the inland boundary of the 
beach, one being the piece of coastline, like so:

  |
C|
  |

(where "C" is the inland beach boundary and "|" is the coastline).

It is possible to model this without a multipolygon, using only one way 
for the beach that shares some nodes with the coastline, like so:

|
|D
|

I understand this is what your plugin does and I'd say it is ok for a 
couple of nodes (for simplicity) but if you really have something like 
an administrative area that ends at the coastline I'd not like to see 
someone "following" the coastline for 100s of nodes. If ways can be 
found to encourage people to use relations in these cases, that would be 
great.

Bye
Frederik