The Mapping of the Ogun State Special Agro Processing Zone is premised on the need to determine the topography of the site and to establish the applicability of Unmanned Aerial Vehicles (UAVs) as an effective tool in surveying. The mapping exercise was carried out from the 2nd – the 3rd of February 2023, while the processing of drone images continued till the 10th of February. The expediency of utilizing UAVs in conducting aerial topography mapping cannot be overemphasized, since their utilization effectively reduces the time and cost of operations. Other benefits of UAVs in this project are that they enabled the teams’ ability to capture accurate and inexhaustible data in both accessible and inaccessible areas. The project site is approximately 479.389 Hectares, and is situated along Iperu/Ilisan road, Iperu, Ikenne Local Government Area of Ogun State, Nigeria.
Core operations carried out during this project include;
- creating workflow,
- data capture,
- data processing and
- producing outputs in the form of very high-resolution aerial imagery and digital terrain model of the project site.
2.0 PROJECT SPECIFICATIONS
The scope of work for this project is as follows:
- Reconnaissance Survey
- Planning, Testing, and Calibration of Drone Instrument
- Flight Planning for Linear (Route) Survey
- Drone Mapping for Data Capture
- Drone Data Processing for Orthophotos
- Deliverables (Softcopy of Orthophoto, Geotiff, and PDF, Photos of the study site)
- Report to be presented using PDF
3.0 PROJECT STRATEGY
The project was carried out in two phases namely,
- Field Work
- Office Work
The deliverables for the project are in softcopy and stated in the table here👉:
Orthophoto Map displays many small pieces of the aerial geotagged photograph, mosaic together and then geometrically corrected and mapped out to their proper scale (this shows the true image of the site route).
3.2 MAPPING APPROACH
The flight plan for the mapping exercise was developed and designed using Ardu Pilot software. Flight simulations were conducted to ensure an effective and optimized flight plan. To capture the surrounding features of the project area, the project boundary was extended by 50 meters.
Dynamic Real-Time Kinematic base station (DRTK2)
Was utilized for the mapping exercise, the base station delivers high-precision positioning data, making it a suitable tool for surveying, aerial inspections, agricultural, and other industrial applications. The project’s horizontal accuracy was 5.46 centimeters
Agisoft Metashape Professional was utilized in processing the drone images. The imagery collected was processed to generate the Orthomosaic of the project site.
CAMERA LOCATION ERROR
DATA PROCESSING LIDAR DJI TERRA
Was utilized in processing drone images. The imagery collected was processed to generate the Digital Terrain Model and Contour of the project site. DJI TERRA was utilized in processing the drone images. The imagery collected was processed to generate the Digital Terrain Model and Contour of the project site.
- Input Data Overview
- Performance Overview
- High-Resolution Orthomosaic
The terrain modeling for the project site was carried out using a plethora of software suites. DJI TERRA was employed to generate high-density point clouds while Quick Terrain Modeler was used to classify the point cloud based on returns and height. The output generated the bare earth elevation for the project site. The final terrain model was plotted within the ArcGIS environment for mapping and presentation. The highest elevation in the project area is between 111.08 – 117.41 meters while the lowest elevation is between 92.19 – 95.65 meters above mean sea level.
The Lidar Survey was completed and on careful analysis of the data acquired, the results of the data processing, and the maps produced, we safely came to the following conclusions: The maps produced as a result of the lidar survey are a true and realistic representation of the terrain of the subject site as at the time the survey was carried out.
The survey was carried out in full accordance with existing specifications, survey laws, and regulations and in compliance with our company’s Quality Control.