A different perspective
Project: Geographic information system oblique imagery
Jurisdiction: Monroe County, N.Y
Agency: GIS Department
Vendor: Rochester, N.Y.-based Pictometry
Monroe County, N.Y.’s Geographic Information Systems (GIS) Department has been incorporating aerial images into its data for several years. In addition to typical aerial or satellite photographs (orthophotos) that are taken from directly above the ground to represent buildings and land features in two dimensions, the county has included oblique aerial images, which are taken from a side view — 40 to 45 degrees — adding a third dimension to objects on the ground.
For instance, an orthophoto may show excellent details of street layouts, but users may have difficulty determining if a flat, black surface is a ground-level parking lot or a rooftop one, or the number of floors in a multi-story building. By combining orthophotos and multi-directional oblique images with GIS data, county employees have a broader view of project areas and the infrastructure details in GIS layers.
All county agencies can access the oblique aerial images, and the GIS Department regularly trains employees to use the images with GIS. “We are always finding ways to enable county agencies to utilize our GIS and oblique imaging data,” says Justin Cole, GIS analyst for the county. “We hold training classes once a month, every month, to bring county and municipal personnel up-to-date on the technology.”
County agencies use the technology for a number of activities, including pre-inspection of infrastructure repairs, sewer investigations, design and construction of the county’s fiber optic network, road striping and bridge maintenance. Dispatchers in the 911 center can view aerial photos of the locations of incoming wireless and landline calls; the fire department uses the data for response planning, training and evaluation; and sheriff’s deputies can access the data on laptops in squad cars.
This year, county planners used the technology to communicate the progress of the construction of a power plant that converts methane gas from one of its landfills to electricity. To reduce residents’ concerns about the 10,000-square-foot facility and help answer their questions, planners combined elevation data with oblique aerial photographs to create three-dimensional computer models that showed the project’s elevation and appearance for members of the legislature, the public and construction companies.