Division 1.1 DefinitionsF1

In addition to the definitions set out in Article 2, the following definitions shall apply:

1. (1)

   ‘digital elevation model’ (DEM) means Digital Surface Model (DSM) or Digital Terrain Model (DTM).

2. (2)

   ‘digital surface model’ (DSM) means a surface describing the three dimensional shape of the Earth's surface, including all static features placed on it. Temporary phenomena do not form part of the surface, but due to the technical difficulties in removing them some of these features may also be present in the surface.

3. (3)

   ‘digital terrain model’ (DTM) means a surface describing the three dimensional shape of the Earth's bare surface, excluding as possible any other features placed on it.

4. (4)

   ‘elevation’ means a vertically-constrained dimensional property of an spatial object consisting of an absolute measure referenced to a well-defined surface which is commonly taken as origin.

5. (5)

   ‘height’ means an elevation property measured along a plumb line in a direction opposite to Earth's gravity field (upwards).

6. (6)

   ‘depth’ means an elevation property measured along a plumb line in a direction coincident to Earth's gravity field (downwards).