[Imports] [MappingDC] Re: Questions about DC import plan

Fri Aug 8 14:37:41 UTC 2014

Thanks, David and Mikel.   After digging through the github repo, I was
able to find the information I was looking for in the makefile and
corresponding commit comment[1].  Apparently, the decision was made not to
use the full DC buildings dataset but a partial dataset produced by OCTO.
 So I suppose the reasoning was that it was worth sacrificing having a
complete DC address database in order to avoid re-importing a bunch of
footprints that already exist.

I'm fairly new to community.  I think better documentation on the wiki and
even github would have been in order, since much of these decisions
appeared to have been been made offline.  Anyone jumping in now should be
able to easily follow the details of the plan, including why choices were
made, without digging through the code or commit messages.

This may be what someone else was concerned about when they mentioned
reservations about an import being conducted primarily by a local
government.  It's great that OCTO have taken the initiative, but their
priorities and concerns would naturally not exactly be in alignment with
those of the OSM community.

With that being said, I applaud all of the hard work that has been done to
make this happen.

-Brandon

[1]
https://github.com/osmlab/dcbuildings/commit/117b1a7636eb04d70e7876eac88eabf6f9b60fc2

On Thu, Aug 7, 2014 at 9:22 AM, Mikel Maron <mikel.maron at gmail.com> wrote:

> > "Will this be taken care of in a separate process that I am unaware
> of?"   No plans for that at this time.
>
> But we (DC OSM community) can start thinking about it. Was decided that
> this after this first "easy" import pass, would look at this harder
> conflation import later.
>
> * Mikel Maron * +14152835207 @mikel s:mikelmaron
>
>
>   On Thursday, August 7, 2014 8:19 AM, David Jackson (OCTO) <
> davidy.jackson at dc.gov> wrote:
>
>
>
> Brandon,
>
> 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
> footprints+addresses?  "
>
> 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
>
>
> 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[1] 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[2] were
> joined to building footprints[3] 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[4]
>
> 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
> footprints+addresses?
>
> 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?
>
> Thanks,
>
> -Brandon
>  @geobrando
>
> [1]http://tasks.openstreetmap.us/job/6
> [2]http://data.dc.gov/Metadata.aspx?id=190
> [3]http://data.dc.gov/Metadata.aspx?id=59
>  [4]https://github.com/osmlab/dcbuildings
>
>
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