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Applied Technology:
Linear Referencing
By Mike Dibble
One of our prospective clients presented us with a
challenge: Could we modify PubWorks to
track work performed on just a portion of a road?
For example, a crew goes out and performs some
activity on Central Avenue between the intersections
of 1st and 3rd streets. Later, the crew works
between 3rd and 5th. Another time, they work between
6th and 7th streets.
A further wrinkle to the challenge was the need to
report on all work done on Central Avenue at the
intersection of 5th Street. So any work performed on
“Central Avenue - 4th through 5th”, or “Central
Avenue - 5th through 6th”, or “Central Avenue - 2nd
through 9th” would be picked up in the report, but
work done on “Central Avenue - 6th through 10th”
would not.
As we searched for a way to meet the challenge, we
decided to borrow an idea from the world of GIS. In
GIS, streets (and roads and highways) are broken up
into linear segments and, in most cases, segments
begin and end with an intersection. By allowing a
PubWorks user to qualify the location on
which work is performed by identifying which
segments were worked on, we would satisfy the
greater level of detail required by the initial part
of the challenge.
In order to satisfy the second part of the
challenge, we needed to go further than the GIS use
of a segment. We had to capture and maintain the
order in which the segments were laid out on the
road – we needed to know that the 2nd Street
intersection comes after 1st and before 3rd. Or that
the Elm Street intersection is the first
intersection between the start of pavement and
before the Maple Street intersection.
Now, if a user wants to know what work was performed
on Central Avenue, at the 5th St intersection, we
can find it and report on it thanks to the layout of
segments using the linear referencing approach in
PubWorks.
To summarize, the features included in this
PubWorks enhancement are:
• The ability to import data from a GIS database and/or export data to a
GIS, or Linear Reference System.
• The ability to break a road into segments. Each segment identifies
where it begins and ends. These begin/end points can
be described in terms of intersections, mile post
markers or where the road begins/ends in your
jurisdiction. Each segment may possess attributes
(e.g. width, pavement type) that differentiate it
from the other segments of the same road.
• Segments making up the road can be ordered.
• Activity locations can be qualified by entering the intersection (e.g.
just 5th Street), an intersection range (e.g. 5th
Street through 10th Street), a segment (e.g. 5th
Street to 6th Street), a segment range (e.g. from
segment #2 to segment #7), mile post or mile post
range.
• PubWorks cost and Activity reports can be produced at a
more detailed level and our reporting system can
search through Activities covering a range of
segments to find those affecting a single segment.
Our Road Segmenting / Linear Referencing
enhancements are scheduled to be released in late
July 2006. For more information please contact
Pete
Anzalone (970) 923-0380.
Table of Contents Volume 2, Edition 2
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