3D slope break lines on Rennes Métropole

This layer of lines filled with information at altitude (Z) combined with a Digital Land Model (MNT) is used to improve the representation of the soil in the context of 3D operations implemented in the territory of Rennes Métropole. The characteristic lines are either natural or artificial corresponding to an infrastructure. All the characteristic lines of the natural terrain, major, dominant, protruding such as dikes, banks, slopes, etc. which have a minimum size (indicated below) are returned. Other important constructions and objects such as roads, railways, bridges, etc. are restored with their characteristics in case they show a discontinuity with the natural terrain. These objects will be returned with their tagging. Soft terrain variations are excluded from the extraction of characteristic lines. The elements returned are as follows: \- The crests and thalweg for a height jump greater than 0.7 puts a slope angle greater than 30° (return of 1 line per crest/thalweg) \- The dikes for a height jump greater than 0.7 m and a slope angle greater than 30° (return of 4 lines for terrain elevations with a flat top, 3 lines otherwise) \- Slopes, cliffs and retaining walls for a height jump greater than 0.7 m and a slope angle greater than 30° (restitution of 2 lines (up and down) per object) \- Ditches for a height jump greater than 0.7 m and a slope angle greater than 30° (return of 4 lines for ground depressions with a flat bottom, 3 lines if not). \- Water surfaces seized at the boundary between water and soil. The water surface is horizontally populated with a Z which corresponds to the mean altitude of the points of the numerical field model on the zone \- Streams with an average width greater than 1.5 m (return by 2 lines on either side of the right-of-way at water level) \- Main roads (return by 2 lines on either side of the right-of-way) \- Railway tracks (return by 2 lines positioned at the side edges of the bench) \- Tunnels (return by 4 lines – 2 high and 2 bass) Accuracy of 3D lines: \- EMQ XY ~ 20 cm \- EMQ Z ~ 30 cm The altimeter reference system is the IGN69.