The Minnesota Department of Transportation (MnDOT) successfully completed their first mobile lidar project with the help of Continental Mapping as part of a Highway 23 reconstruction project.
The project was located 30 miles southwest of Willmar, MN and ran 17 miles from Granite Falls to Cottonwood. The driving factor behind this project was to support and facilitate a stringless paving construction process. The primary deliverables were breaklines and a TIN (in CAD format) that would allow MnDOT engineers to design off of it and, at a later date, a chosen construction firm to load into their stringless paving tools.
To support these needs, MnDOT was in need of very high accuracy data (1 cm vertical accuracy at 1 Sigma). MnDOT turned to their mapping master contract holder - Continental Mapping - to provide our mobile lidar mapping solution. Continental Mapping facilitated all aspects of the project including survey control, acquisition planning, field acquisition, post processing, feature extraction, deliverable creation, quality control, and project management throughout.Continental Mapping utilized its Riegl VMX-250 mobile lidar system to acquire the lidar and ground imagery.
Significant survey control was necessary (laser leveled control at 500' increments with base stations every 5 miles) to tie down the acquisition and mapping effort and provide the accuracy required. Feature extraction focused only on items of interest such as edge of pavement and crown of road. Deliverables included a TIN and breaklines, tiled .LAS files, geo-referenced ground photos, Continental Mapping's Mobile Lidar Imagery Explorer tool for photologging with interaction to Google Earth, and all survey control and notes.
Continental Mapping completed the project in 6 weeks.