100 years ago, on November 11, 1918, World War I came to an end following the signing of an armistice between the Allies and Germany that called for a ceasefire effective at 11 a.m. — it was on the 11th hour of the 11th day of the 11th month.
While the Great War ended a century ago, it is still deeply imprinted in the present-day landscape of the former front zones. The landscape is literally covered with scars of the war: graveyards, remains of trenches, mine craters, and vast areas that still remind of the massive destruction caused by four years of intense artillery shelling, where millions of explosions converted the woods, fields and meadows of Flanders into a lunar landscape by the end of the war. Over 300 mines were detonated in Belgium to undermine enemy trenches, resulting in huge craters. 70 of these craters are — to an extent — preserved today. These destructive imprints did not only destroy human lives but also had a profound impact on the landscape.
LiDAR (Light Detection and Ranging) is a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variable distances) to the Earth. These light pulses — combined with other data recorded by the airborne system — generate precise, three-dimensional information about the shape of the Earth and its surface characteristics. The obtained 3D point cloud is used to create a high-resolution digital elevation model (DEM) of the earth’s surface. As part of the laser pulses penetrate vegetation and reflect from the bare soil below, it has the advantage that tree cover and other vegetation can be filtered out.
In the video below, we visualize the Flemish LiDAR data in LuciadLightspeed V2018 as it supports hardware-accelerated visualization of point cloud data in both 3D and 2D. We zoom in on the village of Wijtschate. Wijtschate, or Whitesheet (as it was known to British troops), is situated on a chain of hills extending south-west and north-east around the city of Ypres in Flanders. Due its elevated position on Messines Ridge and its vicinity to the town of Ypres, Wijtschate was the scene of heavy fighting throughout the First World War. In June 1917, the British undermined one of the highest German positions in Wijtschate with 91,000 lb. of explosives. The explosion created many craters that are still visible today in the shape of deep ponds. While it’s not always clear to distinguish a crater on aerial imagery as some are now (partly) covered with a green mantle of vegetation, the LiDAR data leaves no doubt about it. As we styled the data based on its height, we can clearly identify four craters. They are displayed as black holes because they are so deep that they’re not within the height range that has been defined for the colors.
However the craters act as the opposite of a black hole; they help us to never forget the cruelty of a war.