[Talk-us] Admin boundaries tied to roads

[Brad Neuhauser]

I'd agree with Brett on the boundaries.  The Census data is not
perfect by any means, but it's pretty good, at least in my
area--Minnesota.  (and orders of magnitude better than it was in
2000!)  And if it's not good in your area, you should talk to your
local government and make sure they're participating in the Census'
yearly Boundary & Annexation Survey.
http://www.census.gov/geo/www/bas/bashome.html

>I can tell for sure that they are completely wrong in California. They are not even close to USGS 24k, don't align with official county borders from official sources and don't align with natural features, fences which are sometimes visible on Yahoo.

To further respond to this, there is no claim by the Census that it's
survey accuracy, or that it aligns with other data.  Fundamentally, it
is created by the Census for internal purposes, and all TIGER boundary
data is relative to the other TIGER data. (just like a lot of traced
OSM data is relative to the Yahoo imagery)  Everybody gets access to
it for free and you can use it when its good or ignore it when its bad
or modify it when its in between.  The bigger issue with it being
imported into OSM is the currency, because municipal boundaries are
always changing, and as has been mentioned, boundaries are not usually
something that is easily verifiable "on the ground"

Cheers,
Brad

On Fri, Apr 23, 2010 at 9:54 AM, Lord-Castillo, Brett
<BLord-Castillo at stlouisco.com> wrote:
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> -----Original Message-----
> From: Apollinaris Schoell [mailto:aschoell at gmail.com]
> Sent: Friday, April 23, 2010 9:47 AM
> To: Lord-Castillo, Brett
> Cc: 'talk-us at openstreetmap.org'
> Subject: Re: [Talk-us] Admin boundaries tied to roads
>
>
> On 23 Apr 2010, at 7:13 , Lord-Castillo, Brett wrote:
>
>>> On 19 Apr 2010, at 20:24, Apollinaris Schoell wrote:
>>>> On 19 Apr 2010, at 20:07 , Alan Mintz wrote:
>>>>> Not to mention that merging them will result in the inability to hide these
>>>>> boundaries. When doing a bunch of editing on a road that follows one, in
>>>>> the past, I've taken the time to verify that the boundary doesn't share any
>>>>> nodes with anything and then remove it from my local OSM file manually so I
>>>>> don't have to constantly deal with it. If it shares nodes with anything
>>>>> else, this is no longer possible.
>>>
>>>> fully agree, the good thing is these boundaries are tiger data and bad data anyway and should be replaced with better boundaries
>>>
>>> While I understand the mantra of TIGER=Bad because of the state of the road data, this is not true for the boundary data. Most of the
>>> boundary data comes directly from recorded surveys (something not available for roads) and is not "bad data" for most of the United
>>> States. The rural areas would be the one exception (mostly because they did not have surveys converted to digital layers in 2000), but
>>>  rural areas are also highly likely to have realigned boundary roads that no longer correspond to the original boundaries.
>>>
>> I can tell for sure that they are completely wrong in California. They are not even close to USGS 24k, don't align with official county
>> borders from official sources and don't align with natural features, fences which are sometimes visible on Yahoo.
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> Yes, California is one of the well-known exceptions. Their LUCA program fell apart (and this time around has been split into two separate regions as a result). If you take the Midwest states though, like Iowa, Minnesota, Missouri with their 300+ counties between them, the TIGER lines are directly from official sources, especially the 2009 updates.
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> Brett Lord-Castillo
> Information Systems Designer/GIS Programmer
> St. Louis County Police
> Office of Emergency Management
> 14847 Ladue Bluffs Crossing Drive
> Chesterfield, MO 63017
> Office: 314-628-5400 Fax: 314-628-5508 Direct: 314-628-5407
>
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