NBM v5.0 GRIB2 Section 5 - MDL
IS5: Data Representation Section
| octet(s) | content | value | meaning | notes |
|---|---|---|---|---|
| 1-4 | length of section in octets | 49 | ||
| 5 | section number | 5 | ||
| 6-9 | Number of data points where one or more values are specified in Section 7 when a bit map is present; total number of data points when a bit map is absent | varies by grid (see IS3) | 3744965 (co); 1822145(ak); 76275(pr); 350625(hi); 4573389(oc); 37249(gu); 639999(global) | |
| 10-11 | template number | 3 | Grid Point Data - Complex Packing and Spatial Differencing | |
| 12-15 | Reference value (R) (IEEE 32-bit floating-point value) | varies | ||
| 16-17 | Binary scale factor (E) | varies | See the table below for specific values by element | |
| 18-19 | Decimal scale factor (D) | varies | See the table below for specific values by element | |
| 20 | Number of bits used for each packed value for simple packing, or for each group reference value for complex packing or spatial differencing | varies | ||
| 21 | Type of original field values | 0 | Floating Point | |
| 22 | Group splitting method used | 1 | General Group Splitting | |
| 23 | Missing value management used | varies |
0 - No explicit missing values included 1 - Primary missing values included 2 - Primary and secondary missing values included |
|
| 24-27 | Primary missing value substitute | 9999 | may vary, None (cldlayer/cigp/visp/spc_post); 9.999e+20 (dryts03/spc_post_day3-8) | |
| 28-31 | Secondary missing value substitute | None | nan (dryts03/qmd_rh/spc_post_day3-8) | |
| 32-35 | NG ― number of groups of data values into which field is split | varies | ||
| 36 | Reference for group widths | varies | usually 0 - 1 | |
| 37 | Number of bits used for the group widths (value after - oct 5.36) | varies | ||
| 38-41 | Reference for group lengths | 1 | may vary | |
| 42 | Length increment for the group lengths | 1 | may vary | |
| 43-46 | True length of last group | varies | ||
| 47 | Number of bits used for the scaled group lengths (after - oct5.38 and % by oct5.42) | varies | ||
| 48 | Order of spatial difference | 2 | Second-Order Spatial Differencing | |
| 49 | Number of octets required in the data section to specify extra descriptors needed for spatial differencing (octets 6-ww in data template 7.3) | varies |
usually 1-2 |