David,
We tried for 20 years to get funding to improve coordinate accuracy, and
only succeeded when the obvious need to use GPS to capture living quarters'
locations made accurate street centerlines essential to avoid too high an
error rate in geocoding by coordinate--in other words, when the operational
requirement could be demonstrated. We do realize the broader applications,
and we do have partnerships with many state and local governments and
federal agencies to share data and data maintenance. Where our sources
provide it, we can capture and store more information helpful to routing
(it's in our data model), but most of our input data does not carry it,
from what I have seen, and integrating and maintaining it is not free of
cost. Some of these data have a short shelf life, or at least can be
changed rather easily by a transportation authority that's willing to, for
instance, turn the one-way signs around or eliminate them.
Charles Dingman, Geographer/301-763-1120
4H040, Geography Division
US Census, 4600 Silver Hill Rd Stop 7400
Washington, DC 20233-7400
"David William
Bitner"
<[EMAIL PROTECTED] To
il.com> [email protected]
Sent by: cc
geowanking-bounce
[EMAIL PROTECTED] Subject
Re: [Geowanking] Map Image APIs
04/25/2007 11:03
AM
Please respond to
[EMAIL PROTECTED]
; Please respond
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burri.to
Charles,
I understand that routing improvements are not in the budget as they are
not required for any Census operations. However, The Census Bureau must
realize that they produce the only publicly available nationwide dataset of
this type that has far broader applications than their own internal
business needs. What can we do as a community to try to help secure
funding or to create relationships with other government agencies (federal
or otherwise) to whom these enhancements would be valuable? With a dataset
as import as this street data is, we need to make sure that we keep the
blinders off.
David
On 4/24/07, [EMAIL PROTECTED] < [EMAIL PROTECTED]>
wrote:
I don't think there will be any further releases of TIGER/Line Files (see
http://www.census.gov/geo/www/tiger/future/future_tl.html), though the
information will be released in several other forms, once or twice a
year.
The underlying database will have more accurate coordinate information
for
more counties, as the MAF/TIGER Accuracy Improvement Program completes,
but
new data that would help with routing, such as turn restrictions, speeds,
and one-way streets, are not included. They are not in the budget, and
not
required by any planned operation that would justify them in the budget.
Charles Dingman, Geographer/301-763-1120
4H040, Geography Division
US Census, 4600 Silver Hill Rd Stop 7400
Washington, DC 20233-7400
"Tom Longson
(nym)"
<[EMAIL PROTECTED]
To
m> [email protected]
Sent by:
cc
geowanking-bounce
[EMAIL PROTECTED]
Subject
Re: [Geowanking] Map Image APIs
04/24/2007 05:09
PM
Please respond to
[EMAIL PROTECTED]
burri.to
>From what I understand using TIGER for routing is a bad idea because
TIGER
doesn't say which roads are one way, on ramps, off ramps, etc. Could be
potentially dangerous, although very cool regardless. I personally love
this...
"Graphserver will return an itinerary between any two connected vertices,
even if the itinerary is absurd. In this case traveling by bus and foot
from downtown Seattle to deep within the foothills of the Cascade
Mountians
involves an eight-hour hike from one of the most remote bus stops in the
county." - http://graphserver.sourceforge.net/img/absurd_route_large.png
Anyone have info when the next release of TIGER is expected, and if it
will
have more data to solve some of these routing problems?
Tom Longson
________________
CAR&D / Cars.com
On 4/24/07, Paul Ramsey < [EMAIL PROTECTED]> wrote:
Ryan Sarver wrote:
> We run mapserver internally and I was trying to avoid it as a
> consumer-facing app could be pretty taxing on the system. It's much
more
> fun to use someone else's resources :). But its sounding like that
might
> be my best bet.
Robust at a software level, not so much at a "good answers" level.
Using
TIGER for routing is contraindicated.
--
Paul Ramsey
Refractions Research
http://www.refractions.net
[EMAIL PROTECTED]
Phone: 250-383-3022
Cell: 250-885-0632
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