[Talk-us] [OT] Anyone ever talked about adding more Land Ownership data to OSM?

[Clifford Snow]

On Wed, Jan 9, 2013 at 8:27 AM, Andrew Guertin <andrew.guertin at uvm.edu>wrote:

> I plan to import VT town boundaries from that file at some point, but
> was not planning on touching any of the state boundaries (except to
> connect town boundaries to them). I'd be interested to know how well
> that data source matches others for the state boundary, too, though.
>

Paul Norman got me thinking about the BC/Washington State border. Comparing
Washington State's border files with TIGER data you'll find discrepancies.
I emailed our state's GIS group.  Here is the response I received.

While I cannot speak to the construction of the State polygons in the TIGER
shapefile I can relate why I think the State version is more accurate.  The
version created and maintained by the Washington State Department of
Natural Resources utilizes positions of actual international boundary
monuments that have been coordinated by the National Geodetic Survey (NGS)
or by other surveys performed by licensed land surveyors.

I did some spot checking where we have monument positions and found the
State line to be more accurate than the TIGER representation.  I also
spot-compared the lines to existing features, such as roads running
parallel to the boundary; see a screen shot below where the red line is
TIGER and the green line is State.  The road in question is in fact in
Canada, but the TIGER boundary zigzags from one side to the other.

It looks like there are some other differences between the Washington version
and the TIGER shapefile along the borders of Idaho and Oregon as well.  For
Washington we use survey data where available here as well, but I did not
check as thoroughly to try and figure the differences out.

You might want to check out all of your state's boundaries against Quebec
and neighboring states. I haven't done anything with Washington State. I'd
say something about a rainy day project, but it has been raining here for a
while and will continue until July.

-- 
Clifford

OpenStreetMap: Maps with a human touch
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