Trends Spring 2015 | Page 9

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 communities. 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. Information invaluable “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. TRENDS │9