Sixense Mapping carried out a high density (1000 points/m²) helicopter-borne LiDAR measurement of the summit of Mont Blanc as part of a commercial scientific mission. This measurement, which took place two weeks before the “official” biennial measurement by the French chartered surveyors’ association, is the subject of a detailed article in the December 2021 issue of XYZ, the journal of the Association Francophone de Topographie (French-speaking association of topography).
The use of LiDAR for such a measurement is a first, Mathieu Peyrega, development engineer at Sixense Mapping, explains:
“This alternative method to mountaineering expeditions and conventional topographic techniques allows for a measurement of equivalent accuracy. The result, to our knowledge, is the highest density source of information ever produced on the roof of Western Europe, with an accuracy level fully equivalent to traditional survey techniques.”
In addition to the experimental validation of potentially being able to use our sensors in these extreme conditions, the obtained measurement accuracy (+/- 10cm@95%) is identical to the terrestrial methods and confirms the effectiveness of this technique. The short implementation time makes it possible to use it with a reactivity that is not possible with conventional approaches.
The results obtained, correlated with the weather conditions observed between the two measurements, bring a new perspective on the “short-term” movements of this emblematic peak, which has moved by nearly 13 meters in planimetry and nearly 1 meter in altimetry over the period. In a way, this leads to relativise the “absolute” interest of a centimetric precision measurement in this specific context.
However, for us, this remains an exceptional flight that illustrates the extent of our systems’ capabilities, our teams, and our ‘know-how’.