4947: cave
La Colina 30T 452741 4796892 (Datum: ETRS89. Accuracy code: A) Altitude 210m
Length 2m
Area position

   Sites 4946 - 4948, investigated on the ground a few days before, were positioned on the steep hillside by drone. (Flying level with an opening puts the altitude of the hole at the drone's altitude. The drone's X, Y position is also known so, on a map, a line from the drone's position can be drawn to meet the appropriate contour line. This method can only ever be approximate but is probably better than reading a GPS unit on a steep hillside.)

   Site 4947 is small site choked with mud and rocks.

References: anon., 2019b (Easter logbook)
Entrance pictures : from drone video, April 2019
Underground picture :
Video : Fly past of sites 4946, 4947 and 4948 (YouTube)
Detailed survey :
Line Survey :
On area survey :
Survex file :