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.

For more advanced agencies, the information can keep tax records up-to-date, verify building permits, or establish the user fee for a stormwater utility. “In these cases, the return is generally many times the investment,” says Jeff Liedtke, COO of eMap International in Longmont, Colo.

Finally, agencies that incorporate this aerial imagery and its associated data with emergency management operations will see the payoff as priceless in lives saved.


After collecting aerial images, the next step most municipalities take is to overlay their GIS data onto them. The aerial image is used as a base map, or first layer, to show basic structural information.

Public works departments use a combination of tools, including global positioning systems, to gather information on things like manhole locations, tree location and species, pipe routes and diameter, and street centerlines. Once the location, age, and value of assets are cataloged, the city has a database it can use for budgeting, operations and maintenance schedules, or to monitor depreciation (for GASB 34 compliance, for example).

Unfortunately, not many municipalities have set aside money specifically for such GIS work. “About 15% to 20% of municipalities have a GIS budget, which may cover [the salary of] a coordinator and the GIS work,” says Brian Dubis, GIS project manager with RA Smith & Associates, a consulting firm in Brookfield, Wis.

To get around this obstacle, he suggests, consider adding GIS into the cost of a larger, single project that benefits the entire community. This approach works especially well if you don't have a separate line item for GIS.

Once GIS resources are in place, the annual cost is not as prohibitive as the initial set-up.

“A city of less than 50,000 people should budget $20,000 to $30,000 per year for GIS,” says Dubis. This may include updates to the system, new photography for a growing area, or other related costs.

Zooming in on the future

Aerial digital imaging isn't just a fad.

The practice of overlaying geographic information system (GIS) maps onto aerial digital images is growing. The key to making the most of the technologies is interdepartmental communication.

“The location information and intelligence is very valuable, but it must be better integrated into the overall business,” says Alex Philp, president of GCS Research, an imagery consultant firm in Missoula, Mont. Aerial digital images are most useful when they're shared with a municipality's information technology department, GIS coordinators, and other entities involved in customer service.

And as Web-enabled wireless technology improves, the uses for these images and the GIS incorporated with them is growing.

Brent Elam, P.E., utility engineer in Spotsylvania County, Va., wants to put these moving maps into his vehicles. “GPS would be attached to the truck, and we'd always know where we are” in relation to the site they're trying to reach, he says.

Cash-strapped agencies can use this technology to establish and collect user fees, such as charging constituents for stormwater runoff.

Aerial images, for example, can enable a public works department to calculate pervious versus impervious areas. “Residents can be charged for impervious areas, generating user fees for the city,” says Brian Dubis, GIS project manager with consultant firm RA Smith & Associates, Brookfield, Wis.