To handle the project efficiently, Hanson uses a combination of GIS and mobile
mapping technologies. According to Hanson Assistant Vice President Gary
Rogers, PLS, the firm used GIS technology to capture and manage positions
of the signs. The GIS also contained photos and permitting information.
Some information, such as permit tag numbers, could only be obtained by
visiting each sign. Other data including sign dimensions, milepost and offset
from centerline could be better handled using mobile mapping. Together,
the two technologies could check and supplement one another, enabling
Hanson to set up the sign database for subsequent years.
In the first year of the project, Hanson conducted field surveys at each sign
to develop an accurate baseline inventory of the actual conditions in the
field. Hanson equipped its in-house and contract field technicians with
Trimble GeoXH™ handheld GPS receivers. At each sign, the technician
collected specified information including GPS position and digital photos
as well as the sign’s permit number, type, and condition. According to Rogers,
each technician could visit and collect information on roughly 50 or more
signs on a typical day. Each day’s data were downloaded and sent to
Hanson’s office for checking and processing. The results were then added
into an Esri ArcGIS geodatabase.
To verify the information, Hanson compared the GIS data from the field sur-
veys of the signs against independent measurements. For this, Hanson used
a Trimble MX1 Mobile Data Capture System to rapidly obtain high-quality
acquisition of position and images, and other
data not collected by the field crews, along the
state's controlled highways. Following routes
designed by Hanson’s GIS staff, Hanson’s
mobile mapping vehicle could collect data on
roughly 400 mi (640 km) per day at intervals
of 10 m (33 ft). Over the course of two years,
Hanson collected data along more than
35,000 mi (56,000 km) of highway.
At the end of each day, the mobile data were
transferred to Hanson’s office in Springfield.
Using Trimble Trident Analyst software, techni-
cians inspected each photo to extract sign
position and information including sign face
dimensions, structure type, and distance from
the highway centerline. The completed infor-
mation was combined with the field GIS data.
Rogers is convinced that using multiple Trimble
technologies is key to the project’s success.
“The data collection resulted in a robust inven-
tory of controlled signs and their locations
that were then compared with IDOT’s permit
database,” he said. “We can rapidly review any
changes to the inventory for compliance with
the State’s Highway Advertising Control Act.”
Using the Trimble MX1 to confirm the field
data was essential in meeting the project
goals and produced significant savings in time
and costs. At the end of the first year of the
contract, Hanson had completed and verified
the entire IDOT sign inventory. The information
was added to the state database, where signs
can be compared with existing permits to
identify discrepancies or illegal signs. During
the subsequent years of the contract, Hanson
will use the Trimble mobile mapping system
to detect changes or newly constructed signs
in the field.
The technology provides benefits beyond
the financial aspects. The mapping systems
eliminated the need for field personnel to stop
and work along the state’s busy highways.
This resulted in lower risk of accidents and in-
creased comfort and safety for the field teams.
“It’s an incredibly important tool,” Rogers con-
cluded. “We can collect high-quality data while
moving at highway speeds. It’s fast, safe and
accurate. ”The next time you travel on Route
66, remember that mobile mapping is helping
to keep America’s scenery in view.
See feature article in Professional Surveyor's
March issue: www.profsurv.com