On the request of one of the largest water boards in the Netherlands, HHNK from North-Holland, Skeye performed an aerial photogrammetric survey. The size of the area (over 8 km2) and the limited number of good weather days in February made Skeye decide that this project was best tackled using the Photo-Eye system from a manned aircraft rather than using a drone.
The aircraft flew at a height of 200 meters above ground level. Around six thousand,24 Mp images were acquired in a period of less than 2 hours. On the ground a team established over sixty ground control points and measured an additional a hundred plus control points. This was no easy task as the only way to enter the nature reserve was on foot. The icy Northern wind did not ease matters either. All control was established using RTK GPS.
Upon completion the six thousand images were used to create a digital 3D terrain model using photogrammetric techniques. The resulting terrain model counted over 50 points per square meter. Additionally a orthophoto mosaic was created by correcting all the pixels for colour differences and terrain heights. The result is one image, to scale, that can be used directly in GIS or CAD to obtain coordinates of terrain features.