Wood and Jepsen Consultants (WJC) approached Kahuto about performing an aerial survey. WJC were creating scheme plans for the Sakoca area, which is an informal settlement. The decision was made to use drones for an initial site investigation survey as previously WJC found this task to be a huge time consumption.
The main data requested by our client was:
Geotagged high resolution aerial imagery
0.1 m contours of the terrain
Digital Terrain Model
Digitization of buildings and coconut trees
In comparison to traditional surveying methods, our services were able to provide WJC with:
A large reduction in time spent gathering data
Reduction in risk
More detailed data
Capturing Aerial Images
Flights were conducted using a senseFly eBee drone. GCPs were placed by Kahuto, and the GCP coordinates were gathered by Wood and Jepsen.
Sakoca flight details
Area size: 0.15 km²
GSD: 3 cm/pixel
Number of photos: 284
Altitude: 128 m
Total flight time: 33 minutes
Processing was done with Pix4D, using the following coordinate
Image Coordinate System: WGS84
GCP Coordinate System: Fiji 1986 / Fiji Map Grid (egm84)
Output Coordinate System: Fiji 1986 / Fiji Map Grid (egm84)
In order to create an accurate DTM and contours, the point cloud created in Pix4D was manually classified to remove vegetation, buildings, cars, etc.
Digitization of buildings and coconut trees were done using ArcGIS. 371 buildings in total were digitized.