[ANNEX III U.K. REQUIREMENTS FOR SPATIAL DATA THEMES LISTED IN ANNEX II TO DIRECTIVE 2007/2/EC
1. ELEVATION U.K.
1.7. Theme-specific Requirements U.K.
1.7.4. Requirements for Elevation TINs U.K.
(1) The property values included within a single instance of ElevationTIN spatial object type (TIN model) shall be referenced to one and only one vertical coordinate reference system. U.K.
(2) Triangles intersecting a stop line shall be removed from a TIN surface, leaving holes in the surface. If coincidence occurs on surface boundary triangles, the result shall be a change of the surface boundary. U.K.
(3) The vector spatial objects provided as components of a TIN collection shall fulfil the generic consistency rules provided for vector objects.] U.K.