Method for simultaneously detecting shadows of building roof, building wall body and ground

Abstract

The invention discloses a method for simultaneously detecting shadows of a building roof, a building wall and the ground. The method is implemented according to the following steps. The method comprises the following steps: firstly, calculating a solar altitude angle and a solar azimuth angle at the moment according to the geographic latitude of the place where the digital building model is located, the solar declination (which is an included angle between an equatorial plane of the earth and a connecting line of the sun and the center of the earth) of the day and a solar hour angle (which isan angular distance from a celestial meridian circle of an observation point to a time circle where the sun is located); secondly, calculating the boundary of a shadow area projected on the ground according to the solar altitude angle and the solar azimuth angle; secondly, determining a shadow area boundary projected on the roof by introducing vector data into the DBM; and finally, combining and analyzing the shadow area boundary on the ground and the shadow area boundary on the roof of the building to determine the shadow area boundary on the wall body of the building. According to the method, the relationship between the building and the building shadow can be restored more accurately and more specifically.

Description

technical field [0001] The invention relates to the field of three-dimensional data processing of geographic space data, in particular to a method for simultaneously detecting building roofs, building walls and ground shadows. Background technique [0002] As the demand for urban buildings and the utilization rate of buildings continue to increase, real-time realistic building shadows are attracting more and more attention. Therefore, how to efficiently and quickly visualize the shadows of buildings is of great significance in architectural design, urban planning, urban construction, and urban management. [0003] Existing detection methods for building shadows are mainly based on the geometric shape of the scene, the sun elevation angle, DSM or sensors and other parameters to establish a three-dimensional model to detect building shadows. For example, Zhang Heng et al. improved an automatic shadow detection method based on multi-band spectral differences. It uses the geom...

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Problems solved by technology

[0004] Although the previous shadow detection methods can improve the shadow area detection of buildings to a large extent, most of the methods are only suitable for the shadow area detection on the ground, and for the shadow area on the roof of the building and the building wall in the three-dimensional space There is still no clear detection method for the shadow area on the body

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