CONTINENTAL MAPPING Mapping from Earth, Sky and Spacewww.continentalmapping.com

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In February 2014, Continental Mapping was contracted to map an intersection improvement project for Tennessee DOT (TDOT). This intersection had been an area of concern given the deadly accidents that have occurred there.

The project required large scale mapping using low altitude digital imagery and high resolution airborne lidar. The airborne lidar was essential to characterize the terrain beneath heavily vegetated areas, thereby reducing the need for ground surveys to supplement the terrain data. This expedited the project schedule by delivering accurate 3D terrain data. Low altitude digital imagery was used to accurately survey existing roadway features and pertinent structures within the designat-

ed area of interest.

The aerial survey was accomplished by using state-of-the-art airborne digital sensors. The work was performed at an optimal

time frame when vegetation conditions were dormant. Project data was quickly extracted from original digital sources and delivered within the project performance schedule. The project resulted in current 3D digital mapping data including a terrain file composed of both photogrammetric and airborne lidar elevations. This terrain file

was suitable for use with road design software in project adjusted coordi-nates, per TDOT design specifications.

LOCATION: Grainger County, Tennessee YEAR COMPLETED: 2014OBJECTIVE: Provide high accuracy mapping to support final design for an intersection improvement project

KEY POINTS: • New airborne imagery and lidar for roadway design • Hybrid photogrammetric and lidar terrain model • Fast-track production schedule expediting 3D data to design team • Digital data produced in project coordinates per TDOT design specs

Tennessee DOT Lidar & Photogrammetry