The accuracy of the MDOT centerline is
1:24K based off the initial digitizing of the USGS 7.5 series quads. In areas,
MDOT has adjusted the centerline to mapping grade GPS or more accurate ortho-rectified
imagery. However, MDOT does not claim this accuracy or track it at the
segment level because it is not defined to Map Accuracy Standards (there is FGDC
metadata at the segment level). Currently, MDOT centerlines are used for
planning and asset management purposes and do not require high levels of
accuracy. Engineering level mapping is handled differently and has survey
level accuracies but is not incorporated into the MDOT centerline layer.
Tom
From: Maine GeoLibrary
[mailto:[log in to unmask]] On
Behalf Of Steve Severance
Sent: Thursday, September 18, 2008
8:25 AM
To: [log in to unmask]
Subject: Re: Planning Project
Update
Nate states that the accuracy of much of
the MDOT and E911 road datasets exceeds the initial 1:24K standard. Do
the road segments in either dataset have an attribute to indicate what the
spatial accuracy is? How would I know which roads are accurate to within
40, 20, 10 or say 2 feet?
Steve
From: Maine GeoLibrary
[mailto:[log in to unmask]] On
Behalf Of Kane, Nate
Sent: Thursday, September 18, 2008
7:35 AM
To: [log in to unmask]
Subject: Re: Planning Project
Update
I’ve found that MaineDOT and E911
are the sources that most accurately reflect reality in a vast majority of
cases. There is no better source for road names and address ranges
than E911 roads. MaineDOT’s strength is the linework representation
and associated attributes such as federal functional classification,
jurisdiction, routes, and more. While far from perfect at the scales
commonly used today, it does contain some the most accurate centerline
representations known. MaineDOT also tries to have the road name
attribute reflect the name shown in E911.
Representatives of MaineDOT and E911 have
convened many times in the past to develop common understandings of each
other’s processes, tools and needs in attempts to formulate plans for a
centerline merger. While not completely dead, these efforts have not
resulted in substantial changes in the data (due to differences in
technological tools, the initial expense of time in establishing the
“merged” basemap and the lack of any mandate to do so).
It is worth noting that both centerline
efforts started out as efforts to build and maintain basemaps at 1:24,000 back
in the early to mid 90’s. Both datasets now far exceed this level
of detail. However, with the advent of aerial photos, this data is often
used at scales of 1:1000 or finer. With the same or less staff to handle
this much larger task, it may be some time before the linework hese datasets
can consistently match photos at these scales.
I’ve been in correspondence with
NAVTEQ and given them a copy of MaineDOT centerlines. They stated that
they would evaluate the data to see if they could use it, but even if the
evaluation is favorable, they are actively maintaining their own graphical and
logical representation, which makes it difficult to incorporate large amounts
of changes (as is the case with E911 and MaineDOT). For them, the
motivation to expend large amounts of time and energy is even less, since Maine
is a relatively less-populated state and a majority of their end-users are
tickled if they get within a tenth of a mile of their desired location (think
Mapquest, Yahoo maps, navigation GPS and Google Maps).
___________________________________________
Nathan Kane, GIS Coordinator
Maine Department of Transportation
16 State House Station, Augusta ME
04333-0016
(207) 624-3297, Fax-(207)
624-3301
From:
Sent: Wednesday, September 17,
2008 5:30 PM
To: [log in to unmask]
Subject: Re: Planning Project
Update
Good List, however I would like to mention
that from my preliminary review of the E911 centerlines and MEDOT centerlines
in comparison to centerline of 2 most widely used sources (NAVTEQ and
TELEATLAS) for street data in comparison or overlaid to Google Earth. I
have found that there is a lot of mismatch between Google and our local (E911
& MEDOT) sources.
Has anyone else seen this? What
source is considered to be correct or mostly correct?
All your input would be appreciated as
I’m under a task of developing a new state landbase and then there is
addressing, not address ranges. That is another question that can wait,
but address ranges without knowing what that towns standard (50, 100’, or
200’) becomes very difficult to determine. Then you have towns that
have their parcel data with addressing posted to their websites, but we don’t
have access to that data from the state website.
All input and suggests are welcome.
Thanks,
Greg Davis
Time Warner Cable
P Go Green! Print this
email only when necessary. Thank you for helping Time Warner Cable be
environmentally responsible.
From:
Sent: Wednesday, September 17,
2008 5:02 PM
To: [log in to unmask]
Subject: Planning Project Update
In a continuing effort to keep the
Maine GeoSpatial community aware of the actions taking place on the GeoLibrary
Board's strategic planning efforts, the Sewall Team has summarized input
received from the Maine Geospatial community, the 2002 Strategic Plan and the
GeoLibrary Board and provided the following chart entitled, "Overall Maine
GeoSpatial Listing of Issues and Action Items." The chart attempts
to summarize the action items and issues needing resolution. Each issue
or action item has a "potential solution" indicated for it, a time
frame for implementation and a priority.
We would appreciate it if you could
take a look at this summary and provide us with input on them by sending an
e-mail to: [log in to unmask] with the
subject heading noted as "Maine Stakeholder Input."
Once again, we thank you for your
time and effort.
On behalf of Bill Hanson, GeoLibrary board chair…
Will Mitchell
Mitchell
Geographics, Inc.
Office: 207.879.7769
Fax: 207.221.5861
www.mitchellgeo.com
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