GRIB2 - TABLE 3.4

SCANNING MODE

In Section 3, Octet 72
(For grid templates 0-3, 40-43 and 204)

Revised 01/15/2015
Red text depicts changes made since 08/17/2007



Bit No. Value Meaning
1
0
Points in the first row or column scan in the +i (+x) direction
1
Points in the first row or column scan in the -i (-x) direction
2
0
Points in the first row or column scan in the -j (-y) direction
1
Points in the first row or column scan in the +j (+y) direction
3
0
Adjacent points in the i (x) direction are consecutive
1
Adjacent points in the j (y) direction are consecutive
4 0 All rows scan in the same direction
1 Adjacent rows scan in the opposite direction
5 0 Points within odd rows are not offset in i(x) direction
1 Points within odd rows are offset by Di/2 in i(x) direction
6 0 Points within even rows are not offset in i(x) direction
1 Points within even rows are offset by Di/2 in i(x) direction
7 0 Points are not offset in j(y) direction
1 Points are offset by Di/2 in j(y) direction
8 0 Rows have Ni grid points and columns have Nj grid points
1 Rows have Ni grid points if points are not offset in i direction
Rows have Ni-1 grid points if points are offset by Di/2 in i direction
Columns have Nj grid points if points are not offset in j direction
Columns have Nj-1 grid points if points are offset by Dj/2 in j direction

Notes:

1.  i direction - west to east along a parallel or left to right along an x-axis.
2.  j direction - south to north along a meridian, or bottom to top along a y-axis.
3.  If bit number 4 is set, the first row scan is defined by previous flags.
4.  La1 and Lo1 define the first row, which is an odd row.
5.  Di and Dj are assumed to be positive, with the direction of i and j being given by bits 1 and 2.
6.  Bits 5 through 8 may be used to generate staggered grids, such as Arakawa grids
    (see Attachment, Volume 1.2, Part A, Att. GRIB).
7.  If any of bits 5, 6, 7 or 8 are set, Di and Dj are not optional.



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