Aerial Mapping in Mauritius by drone

Mauritius is an island in the Indian Ocean, 1000km East of Madagascar. This tropical paradise has been inhabited and colonised by various nations since the middle ages, each leaving behind evidence and their customs for the next generation. What  remains is a beautiful combination of East meets West and adds in an African flavour. The climate of Mauritius is very temperate with cool winds blowing in from the sea and a healthy amount of rainfall.

The regulations for flying drones or RPA in Mauritius have yet to be published but recommendations are:
Do not fly your drone over people or crowds of people
Respect other people’s privacy when flying your drone
Do not fly your drone near military installations, power plants, or any other area that could cause concern among local authorities
Do not fly your drone near airports or in areas where aircraft are operating
You must fly during daylight hours and only fly in good weather conditions
Commercial operations follow the same guidelines as above for recreational use.

The site required for survey is located in the center of the island, approximately 450m AMSL measuring 1400ha. The client required very high resolution orthophotos of the site as well as contours of the natural ground level. All this information would be used in the master plan for the development of the site for a new commercial and government facilities hub. Most of the area to be developed is covered in sugar cane plantations as well as some house projects under construction.

 

 

Since the requirement was for high resolution imagery with a pixel size of less than 4cm, it was necessary to fly a lot lower than is standard practice for such and area. This meant that more flying time would be needed to cover such a large area. It was decided to inform the Mauritian Civil Aviation Department of our intentions. The persons contacted were fine with our operations provided we briefed them of our dates, times, positions and elevations. We also used an airband radio on site, making periodic calls to other air traffic, as per ICAO requirements in uncontrolled airspace. No other aircraft were encountered during our operations.

The site was broken up into 5 areas and flight planned to run perpendicular to the wind direction. Each flight was expected to last 1.5 hours, travelling over 50km per session. However the persistent trade winds that blow over Mauritius were severely underestimated by ourselves. This relentless wind from the South East never dropped below 7 knots for 7 days. At times it would gust to 25 knots as reported by Plesance Airfield. The effect of this airflow caused the aircraft to yaw or “weathervane” into the wind reducing efficiency and increasing flight time. All 5 flights were successful with perfect communications, flight characteristics, image quality and landing approaches with a total time of 8 hours spent in from chock to chock. A total of 5600 20mb images were captured.

Control points were kindly provided by the client. These were issued in Local Grid Mauritius 2012 and consisted of concreted “T” designs in the fields as well as on the road edges. A total of 50 were evenly distributed over the site.

Process of this enormous amount of data was handled by our supercomputer in more manageable sections rather as a whole. These sections were later aligned with each other to form a complete model of the site. The end pointcloud consisted of half a billion points. The client received their end deliverables 14 days after being commissioned to undertake the work.

Luke Wijnberg with mapping drone in Mauritius
Luke Wijnberg with mapping drone in Mauritius