Mines des Malécots 1 & 2 and the Tranchée des Malécots
Near to the La Tranchée des Malécots (an old stone quarry) we find the disused Mines des Malécots 1 & 2. These sites lies between Chalonnes- and Rochefort-sur-Loire. These where deep (~300/200m) coal mines. Operational in the 19th and 20th century , with last extraction in 1964.
Photogrammetry is the science of making measurements from photographs, especially for recovering the exact positions of surface points. Images are captured using a 3-way gridded flight plan flown by a Phantom 4 Pro drone; this was pre-programmed before flight. After image capture the photographs are used to render the land surface through parallax colour pixel matching.