Nocturnal Noise Level Indicator - Road

Indicates noise levels induced by road transport Mapping represents isophone curves plotted in increments of 5dB(A) from 50dB(A) The Ln (Night for Night) is the indicator of the average night noise level (22h-6h). The entry was made for a cartographic restitution scale of 1/10,000th. The cards will be updated every 5 years.本数据集表征道路交通引发的噪声水平。其所配套的制图成果展示了以5dB(A)为间隔、自50dB(A)起始绘制的等噪声级曲线（isophone curves）。夜间等效声级（Ln，Night for Night）为22时至6时的平均夜间噪声水平指标。本数据集采用1:10000的制图比例尺。该系列地图每5年更新一次。