2010 Volume 34 Issue 5 Pages 408-417
A GIS digital map on a scale of 1 to 2,500 is generally used for the evaluation of the Environmental Quality Standards for Noise in Japan at the area facing trunk roads. However, it has not been clarified yet whether the digital map with such a scale has an accuracy to apply for the noise estimation. The ground plan of the buildings on the digital map is a roof plan, because the digital map data is made on the basis of aerial photographs. It is feared that the noise estimated by using such a map may have some differences in the effects of buildings on the noise propagation from the real space. On the above view point, surveys and noise measurements are performed to reveal the effect of the accuracy of the digital map in a GIS on the estimation of the road traffic noise for the evaluation of the Environmental Quality Standards for Noise. As a result, buildings on the digital map are a little bigger than those in real spaces, and noise levels predicted by using the digital map are smaller than real noise levels. On the basis of this fact, a method to correct the building area of digital map data is proposed. An additional survey and noise measurement verify that the proposed method is useful for the evaluation of the Environmental Quality Standard for Noise.
