[Talk-us] TIGER 2010 Imports

[Mike N.]

I have looked at some TIGER 2010 extracts in areas I'm familiar with, and have some more concrete ideas to suggest.

Ian may have time to create a customized import tool that will make the whole process much easier.   Here are some ideas for the workflow that should work in both "the boonies" where no work has been done except for US highways and interstates, as well as areas which have had extensive editing.

Users sign up for import on a county-by-county basis so that 2 people don't try to import the same region.
    - Use an OSM wiki page for this, or a Google Docs spreadsheet?

Without getting too specific about the shapefile download and manipulation, "a miracle occurs", and the user is operating JOSM with one layer being a current download of the OSM region in question - a partial or complete county download, and another layer being the TIGER 2010 data.   

  The overall strategy is to generally apply the new geometry / names to the existing TIGER road data.   That retains history and any attributes that mappers have applied.

The tool would "un-abbreviate" both the new and existing TIGER datasets so that name comparisons catch only actual changes.    In addition, the end result of the "Import, merge and review" process is that all TIGER names would be expanded and the tiger:reviewed flag would be removed.   A reference implementation is in 'expand.py' in SVN.

  The tool would operate in "batch mode" - rather than performing 2, 3, or 4 compare operations on each way, then moving on, it is more efficient to compare geometry, additions, and deletions and highlight the differences.   After resolving geometry, next highlight name changes and resolve, etc.

Possible steps:
  1.)   Highlight geometry changes against nearby road with same name and/or TLID.   For each,
      Accept entire way.   New geometry would be projected onto previous way, including intersections and endpoints.
      or - Accept geometry within a constrained area to prevent chaos at the endpoints which have been cleaned up with multiple 1-way "_link" type connections / or short angle extensions, or which connect with an interstate ramp.
     Geometry could be applied where a road has been split for other reasons such as adding a bridge, tunnel or speed limit.   The bridge endpoints would be retained, and the remainder of the geometry applied.

  2.)  Highlight new roads.   Review,  'accept', and the new way would be automatically stitched to the nearest line at the endpoint - which should now be very close since the geometry has been adjusted.

  3.)  Highlight deleted roads.   Review, 'accept' and the old way would be automatically deleted.

  4.)  Highlight name changes.   Review, 'accept', and the name change will be applied to the existing way.
        Complications - roads with multiple names?    Ability to choose "name_1, _2, or _3"?

  5.)  County border line road stitching will likely be a manual operation.

  6.)  Upload and repeat until county is complete.

Complications - 
   If you're not local, you won't recognize new construction VS old / bad geometry; especially if TIGER matches older aerials you're reviewing against.

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   Are there any open source implementations of this sort of tool that would provide more ideas?    I looked at "Road Matcher" briefly, but didn't want to contaminate my thinking by grabbing an idea that might be patented.

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