Grid Definition Template 3.0 - Latitude/longitude (or equidistant cylindrical, or Plate Carree)



Octet No.	Contents
15	Shape of the earth (see Code Table 3.2)
16	Scale factor or radius of spherical earth
17-20	Scaled value of radius of spherical earth
21	Scale factor of major axis of oblate spheroid earth
22-25	Scaled value of major axis of oblate spheroid earth
26	Scale factor of minor axis of oblate spheroid earth
27-30	Scaled value of minor axis of oblate spheroid earth
31-34	Ni - number of points along a parallel
35-38	Nj - number of points along a meridian
39-42	Basic angle of the initial production domain (see Note 1, below)
43-46	Subdivisions of basic angle used to define extreme longitudes and latitudes, and direction increments (see Note 1, below)
47-50	La1 - latitude of first grid point (see Note 1, below)
51-54	Lo1 - longitude of first grid point (see Note 1, below)
55	Resolution and component flags (see Flag Table 3.3)
56-59	La2 - latitude of last gridpoint (see Note 1, below)
60-63	Lo2 - longitude of last grid point (see Note 1, below)
64-67	Di - i direction increment (see Note 1, below)
68-71	Dj - j direction increment (see Note 1, below)
72	Scanning mode (flags - see Flag Table 3.4)


Notes:

(1) Basic angle of the initial production domain and subdivisions of this basic angle are provided to manage cases where the recommended unit of 10^-6 degrees is not applicable to describe the extreme longitudes and latitudes, and direction increments. For these last six descriptors, unit is equal to the ratio of the basic angle and the subdivisions number. For ordinary cases, zero and missing values should be coded, equivalent to respective values of 1 and 10⁶ (10^-6 degrees unit).

(2) For data on a quasi-regular grid, in which all the rows or columns do not necessarily have the same number of grid points, either Ni (octets 31-34) or Nj (octets 35-38) and the corresponding Di (octets 64-67) or Dj (octets 68-71) shall be coded with all bits set to 1 (missing). The actual number of points along each parallel or meridian shall be coded in the octets immediately following the Grid Definition Template (octets [xx+1]-nn), as described in the description of the Grid Definition Section.

(3) A quasi-regular grid is only defined for appropriate grid scanning modes. Either rows or columns, but not both simultaneously, may have variable numbers of points. The first point in each row (column) shall be positioned at the meridian (parallel) indicated by octets 47-54. The grid points shall be evenly spaced in latitude (longitude).