Map Viewing Service (WMS) of the dataset: Noise zones related to major railway infrastructure — Type c chart — Ln index (noise level over a night period from 22h to 6h) — departure from Tarn-et-Garonne

Aggregation of generic tables describing strategic noise maps pursuant to Article 3-II-1°-b of the Decree of 24 March 2006, for an infrastructure, type of infrastructure concerned: rail, type of card c and index Ln. Noise level zones describe a noise exposure situation based on a noise indicator or area affected by noise. They are used primarily for the preparation of strategic noise maps pursuant to Article R.572-5 of the Environmental Code. Noise exposure maps (or type a map) represent the isophone curves of 5 in 5 dB(A). The maps of the areas affected by noise (or “type b” maps) are defined by prefectural decrees. And limit value exceedance maps (type c map) represent for the mapping year the areas where the Lden and Ln limit values are exceeded (the Lden index (equivalent 24h sound level) and the Ln index (noise level over a night period from 22h to 6h)). Data source by infrastructure: CEREMA, ASF本数据集为依据2006年3月24日政令第3-II-1°-b条要求编制的战略噪声地图（strategic noise maps）通用表格的聚合成果，适用对象为基础设施项目，相关基础设施类型为铁路，地图类型为c类，所用噪声指数为Ln。 噪声等级区（noise level zones）基于噪声指标或受噪声影响的区域来表征噪声暴露状况，主要用于依据《环境法典》第R.572-5条编制战略噪声地图。 噪声暴露地图（即a类地图）以每5 dB(A)为间隔绘制等声级曲线（isophone curves）。受噪声影响区域地图（即"b类地图"）由省级政令予以规定。而限值超标地图（即c类地图）则用于表征制图年份内Lden与Ln限值超标的区域，其中Lden指数为等效24小时声级，Ln指数为22时至6时夜间时段的噪声级。本数据集的基础设施相关数据源为CEREMA与ASF。