Determining of shading of single – family detached houses on the basis of data from airborne laser scaning

Abstract

Solar radiation is the fundamental component of physical and biological processes taking place on our planet. It is strongly connected both with the topography of the terrain and with the surroundings: buildings, trees or plants in the direct neighborhood. Shading of any surface is caused by the weakness of stream radiation which can be total or partial. When the object obstructing solar radiation is not transparent, e.g. neighboring buildings, we talk about total shading. In the case when the obstruction is transparent, we talk about partial shading. Trees are an example of objects which are transparent. They are characterized by greater or smaller ability of letting through the solar radiation in dependence from species, height and the crown span.
The literature connected with the solar radiation and determining of shading is based on utilization of diagrams of Sun position. The diagram of Sun position in a graphic way of presenting the position of Sun on the horizon. It illustrates the position of the Sun in the function of time in various days of the year. The first diagrams of the Sun position were introduced by Olgayay A. and Olgyay V. and Mazria caused their dissemination. The diagrams of the Sun position are a universal method of marking the shading of direct radiation for any surface turned in the southern direction, what was reached by the connection to the geometry of Sun position and the intensity of solar radiation.
In the paper, I tried to model shading using GIS tools and the Digital Surface Model (DSM). The individual analysis was conducted for single family houses. The module Spatial Analyst was used which is also a part of ArcGIS environment. This tool can calculate the insolation [Wh/m2] but it does not take into account the reflected radiation. The spatial schedule of shadow was generated from the direct and diffused radiation and their sum – the total insolation. The simulation of changes in shading of single family buildings was created with the regard to the occurrence of elements of the surroundings. The changes of shading were traced in the function of time on the example of a selected day and on span of the calendar year with three month intervals. In addition, the publication concentrates on the potential advantages of using the GIS techniques in the study of the model of shading.