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A bird's eye view

A bird's eye view

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    Pictures a snap

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    This QuickBird satellite image—at a scale of 1:2500—shows Sullivan Gulch and the south tip of the Oregon Convention Center in Portland. The Burnside Bridge is crossing the Willamette River. Photo: GCS Research.

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    Users can retrieve detailed information by overlaying GIS data on an aerial image. This screen capture shows sewer, stormwater, and water information overlaid on the aerial shot. Photo: RA Smith

If someone said all you had to do to make your department more efficient was to take photos of your community from the air, your first response would be, “What's the catch?”

There is a catch. Alone, aerial images won't make your road maintenance team work faster or your sewer mains stop backing up. But when combined with a geographic information system (GIS), accurate data collection, and sound asset-management practices, they can enhance communication internally and with constituents.

The first step in exploiting aerial digital images—collecting the images—can be done as often as needed, depending on how quickly a city is growing or changing.

The city of Mississauga, Ontario, has acquired aerial imagery at scales of 1:6000, 1:8000, or 1:10,000 every year since it was incorporated in 1975. Recognizing that up-to-date imagery is a valuable asset, the city of 660,000 added the cost of aerial photography into its operations budget more than 30 years ago, when its population was only 200,000.

“Flights are planned each spring, before full leaf coverage, to maximize the usefulness of the imagery for photogrammetric data collection,” says David Marion, manager of geomatics with the city's Transportation and Works Department.

The cost of a new flight—with possible repeat flights in areas of high growth—should be leveraged between city departments, including public works, planning, and the assessor's office.

“If you leverage it across multiple departments, the return on investment is better,” says Alex Philp, president of GCS Research, an imagery consultant firm in Missoula, Mont. Smaller cities can pool resources through state agencies and with each other to cut costs and obtain multipurpose imagery.

You also can buy images from the state or county, the U.S. Department of Agriculture, a private image company, or a consultant who can help leverage the information with a geographic information system.

“I use it every day,” says Brent Elam, P.E., utility engineer in Spotsylvania County, Va. “It helps me know how all the pieces fit together, end to end.” He shares the information with elected officials, helping him make his point in discussions. He also shares it with the planning and information systems department, adding to his town's efficiency.

Return on investment is most apparent in the field, when technicians can access data immediately from a laptop or handheld device. Information extracted from the images also can verify as-built with planned development, or determine access to a property.