user-friendly for information that used to be delivered
by telephone to residents.”
Through its contract with Ayres, which recently was
renewed through 2018, the GISC provides detailed
geospatial mapping and surveying services valuable to
virtually every municipal department in Tinley Park and
its 26 other member communities.
Jason Krueger, project manager, and Aaron Sale, flight
coordinator, both with Ayres’ geospatial operations
department in Madison, Wisconsin, explained there are
three aspects to the service Ayres performs for GISC
Work a three-part process
The first is “orthoimagery,” detailed aerial photographs
that provide a horizontal representation of the
community being photographed.
While those orthoimages
are being taken, an Ayres
flight over a GISC community
also uses Light Detection
and Ranging, or LiDAR, a
remote sensing technology
that provides a vertical
representation of everything
in the community.
LiDAR involves a sensor in the
plane shooting pulses of light
at the Earth. Based on the
time it takes a single pulse of
light to reach the Earth and return to the sensor, LiDAR
can determine the elevation at that specific location.
And based on the intensity with which that light pulse
penetrates the surface and then strikes the sensor upon
its return, LiDAR also can determine the density of that
surface. Data analysis reveals whether the surface is
water, bare soil, vegetation, pavement, or some other
man-made material or structure.
When the horizontal
orthoimagery and the vertical LiDAR
information are combined, “basically it is
making our photographs into maps,” Sale said.
More technically known as “planimetric maps,”
these Ayres-generated products provide a detailed
representation of all natural and man-made structures
in a community, information that is invaluable to
community officials in resolving existing problems and
planning for the future.
“When you take those three things together – the
orthoimagery, the LiDAR, and the planimetric maps
– you can make intelligent decisions based on all the
information,” Krueger said.
As one example, Krueger said offic ials in Tinley Park
can deal more effectively with potential flooding
problems because their
planimetric maps show
them where stormwater
will flow and where they
might build retention ponds
to manipulate existing flow
lines and direct water where
they want it to go.
In an average year, Tinley
Park officials receive about
50 calls from residents
wanting to know if their
homes are in a floodplain,
which would require them to purchase expensive flood
insurance. Village staff used to spend 15 to 20 hours
researching each query, Tilton said. But with planimetric
maps, that work now takes little more than an hour.
Through such efficiencies in the conduct of daily
operations, the planimetric data provided by Ayres
results in at least $200,000 annually in “opportunity
savings” for Tinley Park, Tilton said.