{
  "url": "https://openlegislation.uk/eu-regulation-2017-373/annex-VI/division-2/division-Chapter/division-5n1",
  "json_url": "https://openlegislation.uk/eu-regulation-2017-373/annex-VI/division-2/division-Chapter/division-5n1.json",
  "legislation": "eur/2017/373",
  "legislation_title": "Commission Implementing Regulation (EU) 2017/373 of 1 March 2017 laying down common requirements for providers of air traffic management/air navigation services and other air traffic management network functions and their oversight, repealing Regulation (EC) No 482/2008, Implementing Regulations (EU) No 1034/2011, (EU) No 1035/2011 and (EU) 2016/1377 and amending Regulation (EU) No 677/2011 (Text with EEA relevance)",
  "legislation_url": "https://openlegislation.uk/eu-regulation-2017-373",
  "path": "annex/VI/division/2/division/Chapter/division/5n1",
  "kind": "division",
  "number": null,
  "heading": "AIS.TR.355 Terrain data sets",
  "text": "When terrain data sets are provided in accordance with point AIS.OR.355:\n(a)terrain data sets shall contain the digital representation of the terrain surface in the form of continuous elevation values at all intersections of a defined grid, referenced to a common datum;\n(b)a terrain grid shall be angular or linear and shall be of a regular or irregular shape;\n(c)terrain data sets shall include spatial (position and elevation), thematic, and temporal aspects of the surface of the Earth, containing naturally occurring features, excluding obstacles;\n(d)only one feature type, i.e. terrain, shall be provided;\n(e)the following terrain feature attributes shall be recorded in the terrain data set:\n(1)area of coverage;\n(2)identification of the data originator;\n(3)data source identifier;\n(4)acquisition method;\n(5)post spacing;\n(6)horizontal reference system;\n(7)horizontal resolution;\n(8)horizontal accuracy;\n(9)horizontal confidence level;\n(10)horizontal position;\n(11)elevation;\n(12)elevation reference;\n(13)vertical reference system;\n(14)vertical resolution;\n(15)vertical accuracy;\n(16)vertical confidence level;\n(17)recorded surface;\n(18)integrity;\n(19)date and time stamp; and\n(20)unit of measurement used;\n(f)within the area covered by a 10-km radius from the ARP, terrain data shall comply with the Area 2 numerical requirements;\n(g)in the area between 10 km and the TMA boundary or a 45-km radius, whichever is smaller, data on terrain that penetrates the horizontal plane 120 m above the lowest runway elevation shall comply with the Area-2 numerical requirements;\n(h)in the area between 10 km and the TMA boundary or a 45-km radius, whichever is smaller, data on terrain that does not penetrate the horizontal plane 120 m above the lowest runway elevation shall comply with the Area-1 numerical requirements; and\n(i)in those portions of Area 2 where flight operations are prohibited due to very high terrain or other local restrictions or other local restrictions or regulations, terrain data shall comply with the Area 1 numerical requirements.\nThe following diagram contains a graphical illustration of Area 1 and Area 2 terrain data collection surfaces:\nTerrain data collection surfaces – Area 1 and Area 2",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "F",
      "label": "F1",
      "text": "Annex 6 substituted (20.11.2021) by The Aviation Safety (Amendment) (No. 3) Regulations 2021 (S.I. 2021/1203), regs. 1(2), 29"
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eur/2017/373/annex/VI/division/2/division/Chapter/division/5n1",
    "retrieved_at": "2026-11-01T14:45:09.531464+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}