Road Corridor Topographic Survey
Caloundra to Mooloolaba, Sunshine Coast QLD · Client: Civil Engineering Consultancy
Area Scanned
480,000 sqm (12km x 40m corridor)
Time on Site
2 mornings
Sector
Civil & Infrastructure
Deliverables
4 formats
Overview
A 12km road corridor on the Sunshine Coast was being assessed for drainage upgrades and intersection redesign. The civil engineer needed a topographic survey with 25mm contours covering the full road reserve plus 20m either side. Traditional total station survey of this length would have taken three weeks and required extensive traffic management. We flew the corridor with a LiDAR-equipped drone over two mornings, establishing ground control points at 500m intervals along the route. The resulting point cloud was classified to separate ground, vegetation, and built features. A bare-earth DTM was generated at 50mm grid resolution, and breaklines were manually added at kerb lines, invert levels, and retaining walls. Contour plans were delivered in 12A3 sheets at 1:500 scale with full feature coding matching the client CAD standards.
01 Challenge
Dense roadside vegetation obscured kerb lines and drainage structures. Flight operations had to avoid controlled airspace near Caloundra aerodrome. Traffic management for GCP placement required permits from the local council.
02 Solution
LiDAR penetrated the vegetation canopy to capture ground returns at kerb level. Airspace coordination with Caloundra tower was arranged 48 hours in advance, with flights restricted to below 80m AGL. GCP placement on road shoulders was completed at 5am before peak traffic.
03 Outcome
The civil engineer received the full corridor survey in 12 working days, compared to an estimated 25 working days for traditional methods. Contour accuracy was validated at 15 independent check points, with a mean vertical error of 18mm.
Equipment Used
- DJI Matrice 350 RTK
- DJI Zenmuse L2 LiDAR
- Emlid Reach RS3 GNSS
- Pix4Dmatic
- AutoCAD Civil 3D
Deliverables
- LAS/LAZ Point Cloud
- DTM (25mm contours)
- Feature Survey Plan (DWG)
- Ortho-imagery (GeoTIFF)
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