[Imports] [Talk-us] UVM-SAL Buildings

Josh Doe josh at joshdoe.com
Fri Jun 1 03:06:31 BST 2012


On Thu, May 31, 2012 at 9:25 PM, William Morris
<wboykinm at geosprocket.com> wrote:
> Howdy Folks,
>
> Trying this again, after a hiatus, here is a sample of a few hundred
> buildings from a UVM-SAL land use classification. In this case it's
> for an area just west of D.C. in Montgomery County, MD. I offer it for
> your consideration before I pull the import trigger:
>
> http://dl.dropbox.com/u/23616645/Geosprocket_Share/mont_b_1.osm

Thanks for sharing. Spatial accuracy is pretty good for an automated
process (worst I saw was 5m, usually more like 1 to 2m), though not as
good as could be done (very laboriously) by hand given the resolution
of the Bing imagery. I'd tend to say this shouldn't be uploaded en
masse, but rather somewhat selectively, but I'll let the locals make
that call.

There a few issues I see which include:
* Multipolygons aren't tagged with type=multipolygon, and the
building=yes tags should be on the relation, not on the constituent
(inner and outer) ways
* AREA and PERIMETER should not be included as they can be calculated,
and LandCover should not be included unless you can map it to a
sensible (preferably already in use) tag, and since it's all 5 I'm
guessing that's taken care of by building=yes
* Ways are overnoded quite a bit, so run Douglas-Peucker first,
experimenting with epsilon between 1m and 2m

I've been slowly making improvements to the JOSM conflation plugin,
with one goal being to facilitate the conflation of data like this
with OSM. If you could provide a version of this file before excluding
features which overlap existing OSM features, I'd like to try it out
with the plugin to see if it produces useful results. Even better
would be if you could take a look at the plugin yourself and suggest
what enhancements would make it work for this use case. Note there are
a few changes that aren't in the latest JAR available through JOSM.

-Josh



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