North Carolina Department of Transportation Hurricane Helene – U.S. 19 West Roadway Improvements

NCDOT required design-grade topographic survey data deliverables on an expedited schedule to support the safe and efficient engineering design needed to begin recovery.

Aerial imagery/lidar was acquired simultaneously with Riegl 1560II and PhaseOne camera system at an altitude of 3,000’ AGL with 2.5-inch pixel resolution imagery and ~40 ppm2. Field survey included 25 photo-identifiable points and 16 vertical checkpoints. Lidar calibration/classification, analytical triangulation, 1”=50’ photogrammetric planimetric mapping, 1’ spacing DTM(mass points/breaklines) and 3” orthophotography were processed for the entire corridor. All data was developed using the specifications stated in the NCDOT Mapping Manual, Photogrammetry DTM section, and all mapping was compiled to comply with North Carolina Administrative Code 56.1606 (21 NCAC 56.1606).

Final mapping deliverables were in two phases, and included:

Phase I:
o DTM (1-foot point spacing with breaklines)
o Preliminary Uncontrolled Mosaic
o Classified LAS files
o Airborne Survey Report
o IPD Photogrammetry Unit Quality Control (QC) Checklist
o Supporting Documentation/Files
o Exterior Orientation Data
o Control File Information

Phase II:
o Shell Plan Sheet Mapping (3D linework)
o Final Uncontrolled Mosaic
o Revised Airborne Survey Report
o IPD Photogrammetry Unit Quality Control (QC) Checklist
o Supporting Documentation
o AT Report

The data delivered provided NCDOT with an accurate, reliable picture of post‑storm conditions, enabling engineers to confidently plan and design repairs. With this information, the state could move forward rebuilding washed-out roads and rail infrastructure, which would lay the groundwork for safer, more resilient transportation systems and help communities begin the path to recovery.