Contours vector file (NTFC)

Long name NTF Contours
Short name NTFC
File extension(s) .ntf

Land-Form PANORAMA Contour Data in NTF(NTF v2.0 level 1)

Digital Height Data at nominal 1:50 000 scale available as contours or Digital Terrain Models (DTMs), and sold in tiles. Created from Ordnance Survey's "Landranger" paper maps. Geographical features each have individual feature codes. Contours is especially useful for customers who need large areas of height data.

NTF Contours is supported by the GDB library for import and view. Two vector layers may be used to display NTF file's two data set:
  1. point
  2. line

Structure of features

The structure of each different feature is as follows:

  1. Point Feature:(these features are spot heights)
    • a Point Record [POINTREC] 15
    • a Geometry Record [GEOMETRY1] 21
  2. Line Feature:
    • a Line Record [LINEREC] 23
    • and a Geometry Record [GEOMETRY1] 21
    • and maybe one or more Continuation Records[CONTREC] 00 to extend the Geometry Record

When a contour falls entirely within a single tile its first and last coordinate pair are coincident, unless the alignment is broken for clarity or the contour is split into several features. When a contour line crosses a tile edge, the contour line record starts/ends at the crossing point on the tile edge.

Coordinate referencing system

All coordinates are measured from the local origin, which is the South West corner of a tile. To convert coordinate data to full National Grid coordinates, add the coordinates of the feature to those of the South West corner of the tile. The South West corner coordinates are contained within the {X_ORIG} and {Y_ORIG} fields of the Section Header Record [SECHREC].

See UK National Transfer Format (NTF) for information on georeferencing.

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