A.6 zVariables Section

The optional zVariables section contains the definition of each zVariable in the CDF, the values for any vAttribute zEntries associated with each zVariable, and (optionally) data values for those zVariables. The format of the zVariables section is as follows:

#zVariables

[<variable-definition>
 <variable-definition>
 <variable-definition>
           .
           .
           .
 <variable-definition>]

Where <variable-definition> is a zVariable definition. The format of each zVariable definition is as follows:

! Variable        Data        Number                    Record    Dimension
! Name            Type       Elements   Dims   Sizes   Variance   Variances
! --------        ----       --------   ----   -----   --------   ---------

  <var-name> <var-data-type> <n-elems> <dims> <sizes> <rec-vary> <dim-varys>

  !  Attribute           Data
  !  Name                Type           Value
  !  ---------           ----           -----

     [<attr-name>  <entry-data-type>    <entry-value>
      <attr-name>  <entry-data-type>    <entry-value>
      <attr-name>  <entry-data-type>    <entry-value>
           .               .                  .
           .               .                  .
           .               .                  .
      <attr-name>  <entry-data-type>    <entry-value>].         ! Note the "."

   [[<rec-num>:]<indices> = <value>
    [<rec-num>:]<indices> = <value>
    [<rec-num>:]<indices> = <value>
        .            .
        .            .
        .            .
    [<rec-num>:]<indices> = <value>]

Each field is defined as follows:

<var-name>
The name of the zVariable. The name must be delimited with a character not appearing in the name itself (e.g., "EPOCH" or 'Temperature'). The delimiting characters are not part of the zVariable name in the CDF.

<var-data-type>
The data type for the zVariable. The data type must be one of the following: CDF_BYTE, CDF_INT1, CDF_UINT1, CDF_INT2, CDF_UINT2, CDF_INT4, CDF_UINT4, CDF_REAL4, CDF_FLOAT, CDF_REAL8, CDF_DOUBLE, CDF_EPOCH, CDF_CHAR, or CDF_UCHAR.

<n-elems>
The number of elements of the data type. For character string data types ( CDF_CHAR and CDF_UCHAR) this is the number of characters in each string. For non-character string data types this value must be one (1).

<dims>

The number of dimensions for the zVariable.

<sizes>

The dimension sizes --- one value per dimension. If the zVariable has zero (0) dimensions, this field would be left blank.

<rec-vary>
The record variance of the zVariable. This must be either T (the values vary from record to record) or F (the values do not vary from record to record).

<dim-varys>
The dimension variances of the zVariable. For each dimension there must be either a T (the values vary along that dimension) or F (the values do not vary along that dimension). Each dimension variance must be separated by at least one space. If the zVariable has zero dimensions, this field would be left blank.

<attr-name>
The name of the vAttribute for which to specify a zEntry for this zVariable. The vAttribute must have been specified in the vAttributes section. The name must be delimited with a character not appearing in the name itself (e.g., "SCALEMAX" or 'range'). The delimiting characters are not part of the vAttribute name in the CDF.

<entry-data-type>
The data type for the vAttribute zEntry. The data type must be one of the following: CDF_BYTE, CDF_INT1, CDF_UINT1, CDF_INT2, CDF_UINT2, CDF_INT4, CDF_UINT4, CDF_REAL4, CDF_FLOAT, CDF_REAL8, CDF_DOUBLE,
CDF_EPOCH, CDF_CHAR, or CDF_UCHAR.

<entry-value>
The value(s) for the vAttribute zEntry. The format of attribute entry values is described in Section A.3.

NOTE: The last zEntry MUST be followed by a period ( .). If no zEntries are specified for a zVariable, the period must still be present.

<rec-num>
The record number of an zVariable value. This will be present only for record-variant (RV) zVariables.

<indices>
The indices of an zVariable value. The indices are enclosed in brackets and separated by commas (e.g., [23,1] or [1,80]). If the zVariable has zero dimensions, [] would be specified (the brackets are still required).

<value>
The value at the given record/indices. For character string data types ( CDF_CHAR or CDF_UCHAR) the string must be delimited with a unique character and enclosed in braces ( {...}) in the same manner as for an attribute entry for a character string data type. For non-character string data types the value is not enclosed in braces (the braces are not necessary because there can only be one element). The format for CDF_EPOCH values is described in Section 2.2.10.

! Variable          Data      Number                 Record   Dimension
! Name              Type     Elements  Dims  Sizes  Variance  Variances
! --------          ----     --------  ----  -----  --------  ---------

  "Instrument"    CDF_CHAR      10       0              F

  ! Attribute       Data
  ! Name            Type       Value
  ! --------        ----       -----

    "FIELDNAM"    CDF_CHAR     { "Measuring instrument" }.

  [] = { "Gonkulator" }


! Variable          Data      Number                 Record   Dimension
! Name              Type     Elements  Dims  Sizes  Variance  Variances
! --------          ----     --------  ----  -----  --------  ---------

  "Ticks"         CDF_BYTE       1       1     3        T         T

  ! Attribute       Data
  ! Name            Type       Value
  ! --------        ----       -----

  .    ! no attribute entries

  1:[1] = 1
  1:[2] = 2
  1:[3] = 3
  2:[1] = 3
  2:[2] = 2
  2:[3] = 1


! Variable           Data      Number                     Record    Dimension
! Name               Type     Elements  Dims    Sizes     Variance  Variances
! --------           ----     --------  ----  ----------  --------  ---------

  "WIND VELOCITY"  CDF_REAL4      1       3   360 180 10      T       T T T

  ! Attribute       Data
  ! Name            Type       Value
  ! --------        ----       -----

    "FIELDNAM"    CDF_CHAR     { "Wind velocity." }
    "VALIDMIN"    CDF_REAL4    { 0.0 }
    "VALIDMAX"    CDF_REAL4    { 300.0 }
    "UNITS   "    CDF_CHAR     { "Knots" }
    "FORMAT  "    CDF_CHAR     { "F9.1    " }.