Grid 4: Gaussian latitude/longitude grid
Grids
| Octets | Key | Type | Content |
| 7-8 | Ni | unsigned | Ni number of points along a parallel |
| 9-10 | Nj | signed | Nj number of points along a meridian |
| 11-13 | latitudeOfFirstGridPoint | signed | La1 latitude of first grid point |
| 14-16 | longitudeOfFirstGridPoint | signed | Lo1 longitude of first grid point |
| 17 | resolutionAndComponentFlags | codeflag | Resolution and component flags (see Code table 7) |
| 18-20 | latitudeOfLastGridPoint | signed | La2 latitude of last grid point |
| 21-23 | longitudeOfLastGridPoint | signed | Lo2 longitude of last grid point |
| 24-25 | iDirectionIncrement | unsigned | Di i direction increment |
| 26-27 | N | unsigned | N number of parallels between a pole and the equator |
| 28 | scanningMode | codeflag | Scanning mode (flags see Flag/Code table 8) |
| 29-32 | Set to zero (reserved) |
( 1) Latitude, longitude and increments are in millidegrees.
( 2) Latitude values are limited to the range 0-90 000; bit 1 is set to 1 to indicate south latitude.
( 3) Longitude values are limited to the range 0-360 000; bit 1 is set to 1 to indicate west longitude.
( 4) The number of parallels between a pole and the equator is used to establish the variable (Gaussian) spacing of the parallels; this value must always be given.
( 5) The latitude and longitude of the last grid point and the first grid point should always be given for regular grids.
( 6) Where items are not given, the appropriate octet(s) should have all bits set to 1.
( 7) See Notes (6) to (11) under Grid definition latitude/longitude grid (or equidistant cylindrical, or Plate Carrée) page I.2 Bi 8.
( 8) Quasi-regular Gaussian latitude/longitude grids are defined only for subsets of global grids containing full latitude rows (360°).
( 9) For data on a quasi-regular grid, in which all the rows do not necessarily have the same number of grid points, Ni (octets 7-8) and the corresponding Di (octets 24-25) shall be coded with all bits set to 1 (missing); the actual number of points along each parallel shall be coded.
( 10) A quasi-regular Gaussian latitude/longitude grid is only defined for the grid scanning mode with consecutive points on parallels (bit 3 set to zero in Code table 8). The first point in each row shall be positioned at the meridian indicated by octets 14-16 and the last shall be positioned at the meridian indicated by octets 21-23. The grid points along each parallel shall be evenly spaced in longitude.