[Talk-us] parcel boundaries and associated data in OSM

Brian Cavagnolo bcavagnolo at gmail.com
Thu Feb 14 20:29:24 GMT 2013

Hey guys,

In my research group (the Urban Analytics Lab at Berkeley's Department
of City and Regional Planning), we use parcel data for land-use
projection, accessibility, and visualization.  For example, over the
past couple of years we worked with regional government agencies here
in the Bay Area to put together a parcel-level urbansim
(http://www.urbansim.org) land-use model for regional planning
purposes.  We've also developed a prototype 3D visualization tool
(http://www.urbansim.org/Documentation/UrbanVision) to visualize
parcel data, and published on using OSM data for accessibility
calculations [0].  If you poke around the Internet for references to
our director Prof. Paul Waddell you'll get the idea.

We really want a nationwide consolidated, standard parcel database to
build upon.  Such products are available from numerous proprietary
data vendors who make it their business to routinely gather and
consolidate data from local government agencies around the country.
Of course these are often expensive and have restrictions on
redistribution.  Our federal government has been trying for sometime
to create a nationwide public domain parcel database [1][2][3], but
this has not happened.  Many states have managed to consolidate parcel
data (e.g., Massachusetts, Montana, New Jersey).  This is very
helpful, but notable work is required to adapt tools or research from
one state to another.  And our state along with many others has no
such offering.  As a result, parcel data users for whom proprietary
sources are too restrictive or expensive go about manually gathering
the data from county agencies.  If the application doesn't span county
lines, and if the county is open with their data, this may not be a
problem.  But these two conditions are often not both met, driving a
more intensive data gathering effort.  Such efforts are often
duplicated for different projects.  We believe that this landscape of
use and parcel data availability represents an opportunity to form a
parcel data community concerned with building and maintaining an open
nationwide (global?) consolidated parcel database.

This idea is [obviously] inspired by OSM.  And my immediate thought
was, Fun!  Let's add parcel data to OSM!  How do we do that?  This
inquiry has of course led to numerous more detailed questions, the
most fundamental one, of course, being: Is parcel data welcome in OSM?
 I've spent some time reading through the mailing list history.  In
addition to gaining an appreciation for some of the issues regarding
the management of parcel data, I promptly learned that this is a
controversial question.  For each claim that a consensus exists
against parcel data in OSM, a parcel data advocate seems to emerge.
This leads to debate, which seems to focus on a specific set of issues
that I have posed as specific questions below.  I've also dusted off
and enriched the wiki page and associated talk page on the matter
(http://wiki.openstreetmap.org/wiki/Parcel).  My hope is that people
can respond to these questions and we can reach a clear consensus on
{whether,what sort of,conditions under which} parcel data is welcome.
And of course feel free to bring up any issues that are not
represented in this list.  Finally, even if you believe that parcel
data does not belong in OSM, but that a nationwide open consolidated
parcel database would be useful (and possible:) I'm super interested
in this perspective.

Is parcel data useful to OSM?

Can parcel data possibly be kept up to date?

Does parcel data meet the "on the ground" verifiability criteria?

Can tools be adapted to accommodate parcel data density?


[0] http://onlinepubs.trb.org/onlinepubs/conferences/2012/4thITM/Papers-A/0117-000062.pdf
[1] http://books.nap.edu/openbook.php?isbn=NI000560
[2] http://www.nap.edu/catalog.php?record_id=11978
[3] http://www.fas.org/sgp/crs/misc/R40717.pdf

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