[Imports] Questions about DC import plan
David Jackson (OCTO)
davidy.jackson at dc.gov
Thu Aug 7 12:18:12 UTC 2014
To answer your solid questions.
1) " Are these chunks empty because there was found to be no difference
from what already existed in OSM from previous imports? "
No. There are many differences between existing building / address data in
OSM and what is being loaded. Examples included have buildings tagged with
addresses, geometry of data among others.
2) "Why was the decision made to use the tasking manager to conduct a
partial import as opposed to conflating the entire dataset, given that the
new import process is adding not only building footprints but
The goal of the project was to 'complete' or fill in (almost 100%) the
buildings (with address where they exist) for the rest of DC. This means
over 50,000 buildings. The decision was made because to do a partial
import because it would be much less time intensive.
"Will this be taken care of in a separate process that I am unaware of?"
No plans for that at this time.
David Jackson | GIS Analyst | Office of the Chief technology Officer
(W) 202.724.5135 | 200 I ST SE, 5TH FL, Washington, DC
davidy.jackson at dc.gov | Blog: dcaddresscoordinates.blogspot.com
Telework Day: Fri
On Wed, Aug 6, 2014 at 4:44 PM, Brandon Knight <bknight430 at gmail.com> wrote:
> Posting this to the OSM Imports and the MappingDC lists:
> I've been reviewing the work by OCTO on DC building/address imports
> currently being conducted via the tasking manager and I've noticed a few
> things that raised some questions about this plan. Excuse me if I don't
> understand this or if there are obvious answers to these questions. I'm
> new here.
> From my understanding, the current plan is to import all DC buildings and
> addresses in areas that were not imported in 2008-10. Tags were converted,
> building shapes simplified, and then the tags from MAR points were
> joined to building footprints when a building was found to contain only
> one address point, and the point deleted. Data was then split up into
> chunks by block group and converted to .osm files. Scripts found in the
> dcbuildings repo
> After loading some of block group chunks using the tasking manager I've
> found that many are completely empty (0 nodes). The explanation I was
> given by OCTO was:
> " Many of the chunks created by mapbox did not contain any data, this is
> due to the fact that these areas already had complete or near complete
> building / addresses in OSM for that area."
> My questions are:
> 1) Are these chunks empty because there was found to be no difference
> from what already existed in OSM from previous imports?
> I originally thought that the entire DC dataset would be represented in
> these chunks. If chunks containing only "diffs" was the plan, I couldn't
> find a clear description of this or representation in the code.
> 2) Why was the decision made to use the tasking manager to conduct a
> partial import as opposed to conflating the entire dataset, given that the
> new import process is adding not only building footprints but
> I found examples of large areas of block groups with previously imported
> buildings lacking addresses that corresponded to empty chunk files. I
> looked at the raw data and these should contain buildings with joined
> address tags that could be copied to the existing buildings. Currently
> there are large swaths of buildings with no addresses. Will this be taken
> care of in a separate process that I am unaware of?
> I also found previously imported buildings that does not exist in the
> current dataset (or in any satellite imagery that I could find). Since
> this import is semi-automated, wouldn't a comparison of the full dataset
> allowed for someone to spot this and remove it?
> Imports mailing list
> Imports at openstreetmap.org
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