|15||Shape of the Earth (See Code Table 3.2)|
|16-18||Number of grid used (defined by originating centre)|
|19||Number of grid in reference (to allow annotating for Arakawa C-grid on arbitrary grid) (see Note 1)|
1. The number is associated with an attribute of the respective grid description which consists of the centre longitude/latitude and the longitude/latitude of the boundary polygon vertices. variables can be defined on different positions in the triangle.
This leads to different set of geographic locations, e.g.:
1. Triangle (i) (pressure, temperature, ...)
2. Quads (l) (wind velocity ..)
3.Hexagons respectively pentagons (v) (Vorticity,...)