The Long View—

Color Aerial Photography Adds Visual Detail To Newtown’s Geographic Database

By Andrew Gorosko

New color aerial photography of Newtown now in use by the town provides a level of visual detail that was previously unavailable, allowing a clearer interpretation of the natural and manufactured features on the local landscape.

Scott Sharlow, town director of technology and geographic information systems (GIS), explained that the ortho-rectified aerial photography produced by Golden Aerial Surveys, Inc, of Newtown for the town government has been digitized to allow the images to be easily used on computers.

The new color aerial photos, which were created on April 11, 2007, replace a previous set of black-and-white images that were made in 2002, Mr Sharlow said in an interview at the town technology center at Newtown Middle School.

Alicia Messier, a GIS software specialist, aids Mr Sharlow in operating the photographic database for the town.

The color aerial photos were made at a time of day when shadows were minimal, and at a time of year when broadleaf vegetation was dormant to allow a maximum amount of visual detail to be recorded. Also, the presence of shadows in the color aerial photos obscures less visual detail than does the presence of shadows in black-and-white aerial photos.

The color aerial photography is being integrated into the town’s GIS database to provide more visual detail on the physical appearance of local natural and manufactured features than was previously available.

The town’s GIS database consists of a series of electronic “layers” of visual data that are combined and recombined, as needed, to form customized composite images displaying specific information required for municipal planning tasks. The GIS database has approximately 100 layers of information.

Besides aerial photography, the GIS database stores information on land parcels, roads, railroads, brooks, ponds, wetlands, open space, trails, public utilities, industrial development, and land use zones. It includes information on property boundaries, zoning lines, topographic contours, tax assessments, property ownership, building square footages, and land record references, plus other data.

Computerized GIS mapping can be used by every municipal department that stores information that can be keyed to geographic locations, such as street addresses, or lines of latitude and longitude.

The new aerial photography is “planimetric,” meaning that it accurately illustrates the relative horizontal distances between the objects captured in the photos. The photos have been geometrically corrected to provide a uniform scale of distance, making them equivalent to maps in terms of accuracy.

Mr Sharlow explained that the town is using the new aerial photos in conjunction with its revaluation of properties to ensure that its real estate records correspond with existing taxable structures.

Natural Resources

Another valuable use of the new color aerial photography is cataloging local wetland features to aid in enforcing various wetlands violations.

Town Land Use Agency Director George Benson said that the true colors depicted in the new aerial photography has made the photo-interpretation of natural features, especially wetlands, much more direct and apparent than had been possible with black-and-white photography.

The photos also have proven useful in checking on certain earthen disturbances for which required permits have not been obtained, such as some excavations and mining, he said.

“We use it all the time,” he said.

The photos also are valuable for cataloging open space areas, he said.

The 2002 photos can be compared to the 2007 photos to chart physical changes that occurred between those years, he said. Such comparisons can provide information on whether applicable land use regulations were followed during the course of land development, he said. “It does help a lot,” he said.

Mr Sharlow said the new aerial photos can be useful in determining whether certain illegal activity has occurred, including the illegal filling in of wetlands and ponds, as well as the illegal grading of land and illegal sand-and-gravel mining.

“We’re cataloging people doing stuff that’s not good for the public health and safety of residents,” he said.

Color aerial photography is more visually comprehensible than black-and-white aerial photography, he said. It can provide information on changes in stormwater drainage patterns resulting from development.

The new photos have been useful in helping the town plan for the redevelopment of the Fairfield Hills core campus, Mr Sharlow noted.

The new photos meet national mapping standards, providing the town with accurate measurements based on a scale of “one inch equals 100 feet,” he said.

The photos are detailed enough to depict stormwater catch basins that are installed along curbs on roadways. Such visual information could prove useful to the Department of Public Works for planning and maintenance purposes. 

The town received the new color aerial photography several months ago and is now integrating the visual data into its GIS database. The photography cost about $34,000 to produce. The images were recorded on photographic film and then digitized to make them usable on computers.

“It’s money that we’re going to get back, easily,” Mr Sharlow said of the photography’s value to the town.