[Talk-us] tagging a national forest boundary

Greg Troxel gdt at ir.bbn.com
Fri Oct 1 12:37:03 BST 2010

Nathan Edgars II <neroute2 at gmail.com> writes:

> On Thu, Sep 30, 2010 at 9:52 PM, Greg Troxel <gdt at ir.bbn.com> wrote:
>> I think you two might be talking past each other.
>> I am slightly fuzzy on multipolygons, but I think the notion is that a
>> multipolygon has a number of outer rings, and a number of inner rings,
>> and it defines the area that consists of points within an outer ring and
>> not within an inner ring.
>> So in the national forest/inholdings case, I think you have a polygon
>> (closed way) that is the boundary (typically drawn strongly on a
>> traditional topo), labeled as the forest boundary.  Then you have a
>> polygon for each inholding, with no particular tags required.  And then
>> a multipolygon with the forest boundary as outer and all the inholdings
>> as inner.
> Bloody hell, I know this. The problem is that some of the inholdings
> touch the boundary, so they're actually outer ways (and the portion of
> the boundary there is nothing):
> http://www.openstreetmap.org/?lat=28.99352&lon=-81.64891&zoom=15&layers=M&relation=1202373
> Yet the boundary is still something official.

So perhaps our definition of multipolygon is slightly off, and a
containd polygon that is tangent should still be inner.

Are you happy with the rendering now?  It looks like it matches what
you've described.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 194 bytes
Desc: not available
URL: <http://lists.openstreetmap.org/pipermail/talk-us/attachments/20101001/67fef3d7/attachment.pgp>

More information about the Talk-us mailing list