Woolpert was contracted by Hamilton County, Tenn., to acquire and process orthoimagery and lidar data for the compilation of planimetric features, which are used to map building footprints and measure impervious surfaces.
These data will support accurate property appraisals, tax assessments, stormwater management, custom application development and Public Works Department needs.
Under this 18-month project, Woolpert collected 3-inch pixel resolution orthoimagery and 2-points-per-square-meter lidar along with countywide planimetric mapping of building footprints and impervious surface data.
These data were initially processed using a proprietary machine learning program recently patented by Woolpert Geospatial Specialist Daniel Ngoroi. The system employs artificial intelligence and deep learning technologies, algorithms and workflows, integrating disparate data from multiple sources to achieve the highest possible geographic accuracies.
“Using these data, object-based image analysis can allow for precise feature extraction,” Ngoroi said. “Impervious surfaces prevent water from absorbing into the ground, increasing runoff volume, flood risk and urban water pollution. Impervious surfaces can be linked to a particular parcel within a target geographic area for billing purposes through stormwater utilities. This process of defining impervious surface is agnostic and inclusive, and it provides clear, defensible data for each municipality to use as they see fit.”
Woolpert Geospatial Project Manager Volkan Akbay said “Woolpert teams in the U.S. and South Africa performed quality control and manual curation of the planimetric data, which were then delivered in prioritized segments through an Esri ArcGIS geodatabase. This ensured that the information was received in order of need and was accurate and manageable.”
“The amount of vertices produced by these automated impervious surface datasets is out of this world,” Akbay said. “This kind of mapping data is extremely valuable and versatile, but at that volume, the average user is not able to use it effectively. This is where Woolpert’s quality control and patented technologies really complement our remote sensing capabilities. We can collect all the data needed, process it efficiently and accurately, and make it applicable and accessible to each end user.”
Hamilton County Geospatial Technology Manager Jason Shaneyfelt said the planimetric data are already improving efficiencies throughout the county.
“In Tennessee, we are familiar with applying geospatial data to address a wide range of state and local issues,” Shaneyfelt said. “We had been working with multiple vendors over the years and did not have a consistent, updated dataset. We decided that a fresh, accurate countywide dataset was needed, and we wanted Woolpert to provide it. We have worked with their team and Program Director Sam Moffat for many years, and we trust their work. We couldn’t be happier with our decision, the data and the many benefits for the county moving forward.”
