Strategic noise map of type C according to the indicator Lden (day-evening-night) of the network referred to in Loire-Atlantique

Map of type “c” locating the areas of exceedance of the limit value defined for railway infrastructure in Ln, noise indicator in Lden, noise indicator in the day-even-night period, 68 dB(A) — adopted on 11/12/2018. Noise zones are geometrical elements of the strategic noise map. For Type A cards (CBSTYPE), each noise zone is usually bounded by 2 isophone curves (Lden 55-60, 60-65, 65-70, 70-75 and Ln 50-55, 55-60, 60-65, 65-70) or shares the lower limit isophone curve (Lden >75, Ln > 70). For C-type maps (CBSTYPE), each noise zone is delimited by the lower limit isophone curve (Lden > 68 or 73, Ln > 62 or 65). __Origin__ The noise levels emitted by a given infrastructure during an average day are evaluated using numerical models producing isophone curves translated into noise zones, according to the index recommended for all modes of transport at European level, namely the Lden index and the Ln index. The isophone curves, described by the resource N_BRUIT_ISOPHONE_L, are thus used to delimit the external and, where appropriate, internal boundaries of noise zones by index ranges. __Partner organisations__ DDTM Loire-Atlantique __Links annexes__ * [HTML view of metadata on the Internet](http://catalogue.geo-ide.developpement-durable.gouv.fr/catalogue/srv/fre/catalog.search#/metadata/fr-120066022-jdd-5f50f64d-2937-46f8-83a2-9db58b72f0b7) * [XML metadata view](http://ogc.geo-ide.developpement-durable.gouv.fr/csw/all-dataset?REQUEST=GetRecordById&SERVICE=CSW&VERSION=2.0.2&RESULTTYPE=results&elementSetName=full&TYPENAMES=gmd:MD_Metadata&OUTPUTSCHEMA=http://www.isotc211.org/2005/gmd&ID=fr-120066022-jdd-5f50f64d-2937-46f8-83a2-9db58b72f0b7) * [basic URL of wms/wfs services on the Internet](http://ogc.geo-ide.developpement-durable.gouv.fr/wxs?map=/opt/data/carto/geoide-catalogue/1.4/org_38030/f30b1421-bce3-4d80-a07e-74e12a3ee5b4.internet.map) [See this page on geo.data.gouv.fr](https://geo.data.gouv.fr/fr/datasets/4339cbfa4b6d26aa21628e895fde8e40f14c6397)