Filling Out the Field Statistics Class

The <Field_Statistics_Class> groups together a number of statistics calculated across all values that occur in the file for the associated field.

N.B.: What constitutes the "values that occur in the file for the associated field" is ambiguous when this class is used in a Field within a Group_Field. If you must use both grouped fields and field statistics, use the <description> attribute in the <Field_Statistics_Class> to define specifically what values are included.

For additional explanation, see the PDS4 Standards Reference, or contact your PDS node consultant.

Following are the attributes and subclasses you'll find in the <Field_Statistics> class.

Note that in the PDS4 master schema, all classes have capitalized names; attributes never do.

<local_identifier>

OPTIONAL

If you need to refer to this particular set of Field_Statistics from elsewhere in the label, you can git it an identifier here. If you stick to something that looks like a variable name from a typical programming language, you should be OK syntactically.

<maximum>

OPTIONAL

This is the maximum value that is physically stored in the file for the associated field. Any flag values defined in a Special_Constants class are ignored. This value is the maximum before any scaling factor or offset is applied.

I don't understand why there is no <maximum_scaled_value> in this class, as there is for the equivalent <Object_Statistics> class used in Arrays.

<minimum>

OPTIONAL

This is the minimum value that is physically stored in the file for the associated field. Any flag values defined in a Special_Constants class are ignored. This value is the minimum before any scaling factor or offset is applied.

I don't understand why there is no <minimum_scaled_value> in this class, as there is for the equivalent <Object_Statistics> class used in Arrays.

<mean>

OPTIONAL This is the arithmetic mean of the values stored in the file (that is, no scaling and no offsets applied), excluding defined flag values.

<standard_deviation>

OPTIONAL This is the statistical standard deviation of the values stored in the file (that is, no scaling and no offsets applied), excluding defined flag values.

<median>

OPTIONAL This is the median value stored in the file (that is, no scaling and no offsets applied), excluding defined flag values.

<description>

OPTIONAL Use this free-format text field to provide any relevant explanatory notes or caveats.