The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
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Articles | Volume XLIII-B2-2022
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLIII-B2-2022, 1009–1016, 2022
https://doi.org/10.5194/isprs-archives-XLIII-B2-2022-1009-2022
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLIII-B2-2022, 1009–1016, 2022
https://doi.org/10.5194/isprs-archives-XLIII-B2-2022-1009-2022
 
30 May 2022
30 May 2022

ANALYSIS OF SUN GLARE ON ROUNDABOUTS WITH AERIAL LASER SCANNING DATA

S. M. González-Collazo1, J. Balado1, E. González1, and M. Soilán2 S. M. González-Collazo et al.
  • 1Universidade de Vigo, CINTECX, GeoTECH Group, 36310 Vigo, Spain
  • 2Department of Cartographic and Terrain Engineering, University of Salamanca, Calle Hornos 9 Caleros 50, 05003, Ávila, Spain

Keywords: solar incidence, road geometry, safety, driver’s bearing, ALS point clouds

Abstract. Road geometry and sun glares play an important role concerning road safety. In this research, the direct sunlight in a roundabout sited in Ávila (Spain) is analysed using Aerial Laser Scanning (ALS) point clouds. First, the roundabout is divided in 8 sections, obtaining the driver bearing vectors of the roundabout. Entrances and exits driver bearing vectors of the roundabout are also considered. Then, sun rays are generated for a specific location of the roundabout and in a specific day and time. The incidence of the sun rays with the driver’s vision angle is analysed based on human vision model. Finally, intersections of sun rays with obstacles are calculated utilizing ALS point clouds. ALS data is processed (removing outliers, reducing point density, and computing a Delaunay Triangulation) in order to obtain accurate intersection results with obstacles and optimise the computational time. The method was tested in a roundabout, considering different driver bearings, the slope of the road and the elevation of the terrain. The results show that sun glares are detected at any day and time of the year, therefore areas with risk of direct sun glare within the roundabout are identified. The sun ray’s incidence in the vision angle of the driver is higher during winter solstice, and intersections with obstacles occur mainly during sunrise and sunset. In roundabout vector 7, during winter solstice there is direct sun glare for 7 hours 30 minutes, at the equinoxes for 6 hours 15 minutes and during summer solstice there is no direct sun glare.