27.03.2020 - Airborne laser scanning data has been used as basis for orienteering maps for over 10 years. The precise geodata is available at Swisstopo only up to 2100 m above sea level. However, several stages of the Swiss O Week 2021 in Arosa will take place in challenging areas above tree line. The use of a drone was tested for the first time using a Matura thesis in order to provide the orienteering cartographer with more accurate and up-to-date basic data.

To obtain the basic data, Marius Robinson, student at the Kantonsschule in Chur, went into the area above Arosa with a DJI Phantom 4 drone. All in all, it took three flights, each 15 – 20 minutes long, to fly about 90 to 150 m above the ground covering the 0.5 km2 test area. The drone, which was provided by Meisser Vermessungen AG Chur, took around 1100 photos with a resolution of 4-5 cm/pixel. Using a computer program, these images were then used to create an altitude model and orthophoto with the same high quality. The difference is huge compared to the basic data by Swisstopo with a resolution of 50 cm/pixel! This much more detailed drone data is saving lots of time especially when drawing point and line objects such as stones, rocks, stony areas, single trees, streams, etc. Also contour lines and artificial objects could be drawn much faster.

In the test area on the Aroser Weisshorn, Marius ultimately saved about a quarter of the time using the drone data, as compared to a similar area he had mapped in the conventional way with data from Swisstopo! Based on these first very positive experiences, it was decided to use a drone again flying over the area of the 3rd stage of the Swiss O Week in the Urdental. Thus, Beat Imhof was already able to map the site using the new detailed basic information in autumn of 2019.


Drohnenkarte  Flugfoto1  Flugfoto2  

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