Skeye BV was asked by the municipality of Rotterdam to map an industrial plant in the harbor of Rotterdam. Aim of the city council was to se if surveying using a drone was a good method to obtain results in a fast manner with high quality.
Normally the use of unmanned aircraft is restricted up to a height of 400 feet above ground level. This was not possible on this project as there was a building of more than 100 meters on the terrain as well as a chimney stack of more than 125 meters. A special permission was obtained from the authorities to be allowed to fly higher.
The Microdrone MD4-1000 multicopter of Skeye flew at a height of 150 meters above ground level and collected high resolution imagery at predefined positions. On the ground a number of survey markers were installed and measured using RTK GPS. The markers had to be constructed especially for this project as the standard markers that are normally used would not be visible from a height of 150 meters.
The end delivery to the client consisted of a height model and an orthophoto mosaic to scale. In addition a terrain model was produced by removing all measurements that were not on ground level.
A quality control check was carried out using an additional 39 heights on the ground with the RTK GPS. The average difference turned out to be 42mm.