PDS4 Character Data Type Definitions

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Following is a glossary of data type definitions, extracted from the PDS4 Information Model and master schema. They are used to describe fields defined in local and discipline dictionaries as well as values included in data objects (tables and arrays, for example).

Last update: 2014-07-17, A.C.Raugh

ASCII Representations

ASCII_AnyURI
Use this for fields that are intended to be interpreted as Uniform Resource Identifiers (URIs). PDS restricts these strings to the Latin character set, so you should URL-encode any non-ASCII characters in your URIs.
ASCII_Boolean
This corresponds exactly to the XML Schema data type of "boolean". Valid values are "true", "false", "1" (one), and "0" (zero).
ASCII_Date
This data type holds a calendar date only (that is, without a time element), in either the standard YYYY-MM-DD format or the alternate YYYY-DDD format. The date may be preceded by a negative sign for negative UTC years (year -1 UTC is year 2 B.C.). You may truncate the value to the appropriate accuracy (so day and month may be excluded if only the year is known). Do not include the hyphen separator for fields that are omitted (that is, use 1977, not 1977--). The Z suffix indicating a UTC date is prohibited in these values.
Usage Note: The date itself is not validated beyond simple numerical ranges, so PDS schema validation will not warn you, for example, that 2001-02-29 is not a valid date.
ASCII_Date_DOY
This data type is identical to the ASCII_Date type except that the date must be in the day-of-year format.
Usage Note: The date itself is not validated beyond simple numerical ranges, so PDS schema validation will not tell you, for example, that "1999-366" is not a valid date.
ASCII_Date_Time
This data type is the most general way to indicate a calendar date with a time. It is in one of the standard formats YYYY-MM-DDThh:mm:ss.ssss or YYYY-DOYThh:mm:ss.ssss. It can be truncated to the appropriate accuracy, even back to just a year value. You may precede the year with a negative sign for negative UTC years (the year -1 UTC is the same year as 2 B.C.). You may also include a 'Z' at the end of the string to indicate the value is a UTC date/time.
Usage Note: The date itself is not validated beyond simple numerical ranges, so PDS schema validation will not warn you, for example, that 2001-02-29 is not a valid date.
ASCII_Date_Time_DOY
This data type is identical to the ASCII_Date_Time type, except that the date portion must be in the day-of-year format.
ASCII_Date_Time_UTC
This data type is identical to the ASCII_Date_TIme type, except that the value must have the Z appended to the end to indicate that the value is a UTC date/time.
ASCII_Date_Time_YMD
This data type is identical to the ASCII_Date_Time type, except that the date portion must be in the year-month-day format.
ASCII_Date_YMD
This data type is identical to the ASCII_Date_YMD type, except that the date must be in the year-month-day format.
ASCII_Directory_Path_Name
Use this data type for path information. It is constrained to use only the Latin (i.e., ASCII) character set.
Usage Note: All paths in PDS4 labels should be specified using Unix-style notation, and should never be absolute (so they should never begin with either a device identifier or a slash character). This will also typically be true for paths that appear in archival tables, but check with your PDS node if this presents a problem. The schema validation does not enforce these constraints. You should also not assume that fields with this data type include a trailing slash character.
ASCII_DOI
This is a string corresponding to a DOI of the form "10.string/string", where string can be any sequence of one or more non-whitespace characters.
ASCII_File_Name
This data type is a string representing a file name without path information. The characters are constrained to be in the Latin subset (i.e., ASCII).
Usage Note: Do not assume that any validator will check for file existence unless it specifically claims to do so. Schema validation is very simple and will not, for example, tell you that you have included path information (as indicated by the presence of a slash character), or included values that would be problematic for some or all operating systems (like the asterisk or question mark characters).
ASCII_File_Specification_Name
This data type is for file names with path information. It is effectively the concatenation of the ASCII_Directory_Path_Name and ASCII_File_Name, with an additional slash character as needed. The Usage Notes for those data types apply here as well.