
Date:
Location:
Project:
Jan, 2019
Sihanoukville,Combodia
Phase-2 planning and earthwork engineering for tourist resort development


Background
This resort is to be constructed on a terrain near the seashore, with elevation between 25-75m. 85% covered by trees.
Phase 1 was already finished, like primitive roads, prefabricated houses.
Phase 2 is for further constructions for standard roadway systems, resort villas, casinos, golf club, etc.


Requirements
Area Size: 1,419 hectares
Service: 1:500 topographic survey
Output Demand: DEM/DTM, contour lines,vector line map, DOM
Accuracy Expectation: 10cm vertical
Project Duration: one month


Preparations
1. 2-days site visit, to select a location for a GNSS base station, which should be almost the center of the zone to cover the area within 20km radius) and locations for take-off and landing.
2. Established 19 GCPs (ground control points), to determine flight altitude of aerial laser scanning and aerial imagery capture.

Fieldwork
Part 1: LiDAR survey - aerial data capture
Equipment: UAV-based LiDAR system, multi-rotor UAV + Mini LIDAR system SZT-R250 (measuring range 250m)
Part 2: UAV photogrammetry - orthophoto imagery data capture
Equipment: VTOL fixed-wing drone with 42MP camera
28 flights in total, 6 days to accomplish



Data Process
Accuracy verification: 1 day
DEM/DTM, contours, vector line map: 10 days
Orthophoto map: 4 days
Accuracy verification results:
Standard deviation just 0.056 cm, less than 10 cm
