Introduction Gully erosion is a worldwide phenomenon causing permanent degradation

To fulfil the requirements of multi-temporal change detection, the gully headcuts need to be referenced identically. For this INT-777 purpose, as well as for registering data coming from different acquisition systems, a stable local reference system was defined. Four fixed reference points were installed on the fundament of utility poles in distances not further than 700 m. Ground control points (GCPs) were measured with a total station and registered to the fixed reference points by a free network adjustment. Resulting accuracy of GCP measurement and subsequent registration is about 5 mm. Two different types of GCPs were used which are ectoderm adapted to each image acquisition configuration. Both types are generally defined by a white circle on top of a black board. The GCPs for aerial image recording have a diameter between 5 and 10 cm. In both field campaigns, five of them were evenly distributed at different terrain heights. To prevent disturbances of the gully morphology, the GCPs were installed at the surrounding of the headcuts within the agriculturally used area (cf. Fig. 3). GCPs for terrestrial image recording have a diameter of 2.5 cm and were applied close to the gully edge within gully walls.