On 2/21/2013 7:27 PM, Brian Cavagnolo wrote:
Hey guys,
In a previous thread on parcel data, some people expressed interest in
participating in creating some sort of open repository for parcel
data. I was imagining a conference call or something to discuss next
steps, but I think we can advance with email. I'm imagining that it
makes sense to separate the data gathering process from the data
standardization/import process.
Regarding the data gathering, the main objective is to gather recent
raw data, licensing terms, and meta data from jurisdictions in
whatever form they make it available, organize it in a dumb directory
structure. I was just going to set up an FTP (read-write) and HTTP
(read-only) server to get this going. Are there any
recommendations/opinions on a longer-term approach here? Custom
webapp? Off-the-shelf webapp? Somebody mentioned a git repository.
Regarding standardization/import, I was planning on setting up an
empty instance of the rails port as a test bed. Then participating
users could point JOSM and other tools at this alternative rails port
to examine, edit, and import parcel data. We could also provide
planet-style dumps and mapnik tiles. The idea is that we would have a
safe place to screw up and learn. Does this sound like a reasonable
direction?
Oh, and I found this fantastic paper that some parcel data people (Abt
Associates, Fairview Industries, Smart Data Strategies) recently put
together for HUD [1] that examines many of the issues that they faced
building a parcel database. Timely.
Ciao,
Brian
[1]
http://nationalcad.org/download/the-feasibility-of-developing-a-national-parcel-database-county-data-records-project-final-report/
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Hi Brian,
I am interested in collaborating on this. So here's some thoughts:
From my perspective (and I think others as mentioned in other email
threads), the main thrust of utilizing parcels is a source of addresses
based on parcel centroids where address points or buildings with
addresses are not available. In addition, several people have mentioned
they utilize parcels as an overlay to assist with digitizing. The
current consensus is that parcels should not be imported as a whole.
I think this project needs to dovetail / build upon the work that Ian
Dees started with finding sources of address data. Parcel polygons are
one potential source. However, parcel polygons are valuable by
themselves, so we should be documenting all available sources of parcel
data as we pursue addresses.
I also think we need a little bit more sophisticated Data Catalog than a
google spreadsheet. We need to capture more information and a
spreadsheet gets a bit unwieldy after so may columns. I've got a
prototype that I am working on getting out in the wild soon, but
basically its a web form that people register to use and the info sits
in a database.
A by-product of the effort to identify, catalog, gather raw data, etc.
would be having a central location for storing raw parcel data that is
not readily downloadable. For example, someone happens to have a copy of
X county parcel data that they had to send a check for $25 to acquire,
they received it on CD, and they would like to donate it to a central
repository. This is assuming there are no restrictions on the data. It
sounds like you're willing and able to donate disk and bandwidth to
support this effort. I don't see a need to make a copy of data that is
already sitting on the web.
As far as standardization/import and the rails server - I think this is
not the right path to take. As mentioned above, we shouldn't be
wholesale importing parcels. Now you could do some standardization of
parcel data for example to render polygons by land use codes and show
single family, multi-family, commercial, government, etc land use types
as an overlay layer for reference, but that is a huge effort by itself.
Users knowledgeable about parcels in their state or local area could
serve up something like this as a reference, but the goal is not to
standardize the parcels and import them.
So, continuing on from the raw data gathering, taking it one step
further, some organization could gather up the freely downloadable data
plus the data sitting in this repository and serve up a WMS layer or
tiles of parcel polygons. And this could be the goto source for a parcel
overlay for the OSM community members interested in utilizing a parcel
overlay layer for editing.
Email and a wiki page sounds good to me for coordination. Maybe we can
bring it up in a Mappy Hour as well. And if there's enough of a need, we
could do a separate parcels / address oriented Google Hangout. Sounds
like Serge is already organizing something similar, and maybe we just
particpiate in that to start, since there's a lot of overlap.
Thanks for sharing the link to that document. Its an awesome document.
For anyone wanting to learn more about national parcel data issues -
this is it! I know one of the authors, and all three of them have been
studying and thinking about this issue for literally decades. Its a
great read, if you're into that kind of thing.
Brian
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