After the severe storms that bashed the South coast of the UK, Skeye was asked to perform an aerial survey of the breakwater that lies at the entrance of the harbour of Plymouth. Skeye carried out this aerial survey in close cooperation with it’s sister company Deep from Amsterdam that was responsible for measuring the breakwater below the water level. In mid March Skeye mobilised to Plymouth so as to catch a rare window of good weather in combination with a spring tide. This spring tide was required so as to give Skeye the opportunity to collect as much data as possible from then air at low tide whereas Deep could collect as much data as possible at high tide. This was done in order to create two datasets that would overlap sufficiently so as to be able to check the accuracies of both datasets.
The breakwater is close to a mile long and around 50 meters wide. Skeye conducted five separate flights using the Microdrone MD4-1000 multi-copter at a height of 50 meters. In total over 600 images of the breakwater were taken. In addition over 30 ground control points were established on the breakwater as well as over 60 additional control measurements. All control was measured using a RTK GPS in addition to the RTK correction signals from Smartnet Europe.
All the collected images, each 24 Mp were joined to create a 3D model of the breakwater. Heights were extracted with a point density of over 50 points per m2. Subsequently the individual images were merged to create a seamless orthophoto mosaic whereby each pixel was corrected for geometry, height and colour.
Deep used a multibeam echosounder to create an under water 3D model. The datasets of Deep and Skeye were then joined together and checked for the required accuracies.