Areas and Areas of clearance related to T8 easements (Radio Reception Centres) in Pas-de-Calais

T8 easements are radio easements for the protection of air navigation facilities (navigation and d & #x27 facilities; airport landings, national meteorological transmitter centres and radio beams) They fall under the same texts as PT1 and PT2L' base of #x27; a servitude is the space field (i.e. geographical area) to #x27; within which s & #x27 applies the easement. This space field can be defined either in 2D or 3D in particular in the specific cases of airport release easements, radio transmission centre protection easements.L'base includes primary clearance zones, secondary clearance zones, special clearance zones and areas of clearance.The maximum distance between the limit of #x27; a radio centre and the perimeter of the servitude zones may not exceed:- 2,000 metres in the case of #x27; a secondary clearance zone;- 400 metres in the case of #x27; a primary clearance zone surrounding an aeronautical safety facility or a radio-goniometric centre;- 200 metres in the case of #x27; a primary clearance zone surrounding a centre other than those mentioned above;- 5,000 metres in the case of #x27; a clearance area.The maximum width of #x27;a special clearance zone protecting a radio link, between two fixed points counted perpendicularly to the radio wave path axis may not exceed 50 meters on both sides and d' other of the ellipsoid of the hertzian beam. In practice, the beam is assimilated to a band and l' plate shall not exceed 50 m on either side and d'other of the axis.The maximum width of\#x27; a clearance area protecting a radio-tracking or radionavigation station shall not exceed the width of the angular sector explored by the station, increased, if necessary; there is a safety margin of d' a safety margin of not more than one degree beyond the two limits of this area. __Origin__ The boundaries of a sector are shown on the graphical documents of the municipal map. They generally correspond to the limits of d' an aggregate of cadastral plots. The geometry of cadastral plots is a data derived from the cadastral geographical reference chosen at the time of the; elaboration of the document d' urbanism. This cadastral geographical repository can be either the Parcellar BD provided by the ¨#x27;IGN, or the computerised cadastral plan (CCP) provided by DGFiP. __Partner organisations__ DDTM Pas-de-Calais __Links annexes__ * [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-8b4a49bd-37b4-4651-a8f2-f2a918fcd360) * [COVADIS data standard: Area of the municipal map](http://geostandards.developpement-durable.gouv.fr/afficherPageStandard.do?jeu=N_SECTEUR_CC_ccccc) [See this page on geo.data.gouv.fr](https://geo.data.gouv.fr/fr/datasets/39dee0c2b648ee9a7fd9a07e06e7adb9d4c555e0)