gis-tools-ts - v0.6.0
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    Function grib2Template52

    • Data Representation Template 5.2 – Complex packing (no spatial differencing).

      Reads and parses the metadata fields defined by GRIB2 Template 5.2. For most templates, details of the packing process are described in Regulation 92.9.4.

      Parameters

      • section: Reader

        Binary reader providing access to the section data.

      Returns {
          binaryScaleFactor: number;
          decimalScaleFactor: number;
          groupLengthFactor: number;
          groupSplittingMethod: { code: number; description: string };
          groupWidthsBits: number;
          missingValueManagement: { code: number; description: string };
          nBitsGroupLength: number;
          numberOfBits: number;
          numberOfGroups: number;
          originalType: { code: number; description: string };
          primaryMissingValueSubstitute: number;
          referenceForGroupLengths: number;
          referenceForGroupWidths: number;
          referenceValue: number;
          secondaryMissingValueSubstitute: number;
          trueLengthOfLastGroup: number;
      }

      Object containing the fields of Template 5.2.

      • binaryScaleFactor: number

        Binary scale factor (E). Octets 16–17.

      • decimalScaleFactor: number

        Decimal scale factor (D). Octets 18–19.

      • groupLengthFactor: number

        Length increment for group lengths. Octet 42. Used in the formula: Lₙ = ref + Kₙ × len_inc.

      • groupSplittingMethod: { code: number; description: string }

        Group splitting method used. See Code Table 5.4. Octet 22.

      • groupWidthsBits: number

        Number of bits used for the group widths (after subtracting the reference value). Octet 37.

      • missingValueManagement: { code: number; description: string }

        Missing value management. See Code Table 5.5. Octet 23.

      • nBitsGroupLength: number

        Number of bits used for scaled group lengths (after subtracting ref and dividing by the length increment). Octet 47.

      • numberOfBits: number

        Number of bits per packed value for simple packing, or per group reference for complex packing. Octet 20 in the documentation.

      • numberOfGroups: number

        Number of groups of data values (NG). Octets 32–35.

      • originalType: { code: number; description: string }

        Type of original field values. See Code Table 5.1. Octet 21.

      • primaryMissingValueSubstitute: number

        Primary missing value substitute. Octets 24–27.

      • referenceForGroupLengths: number

        Reference for group lengths. Octets 38–41. The group length (L) is the number of values in a group.

      • referenceForGroupWidths: number

        Reference for group widths. Octet 36. The group width is the number of bits used for every value in a group.

      • referenceValue: number

        Reference value (R) (IEEE 32-bit floating-point). Octets 12–15 in the GRIB2 documentation.

      • secondaryMissingValueSubstitute: number

        Secondary missing value substitute. Octets 28–31.

      • trueLengthOfLastGroup: number

        True length of the last group. Octets 43–46. A special-case group length if the sequence doesn’t fit the formula.