Represents the "PDU" entry of the geospatial measure dictionary object.

It is an optional entry defined as part of the PDF 1.7 Extension Level 3 specification.

It contains an array which contains strings, representing PDF name objects.

Items in this array may take one of the following valid values:.

• .
• M
• KM
• FT
• USFT
• MI
• NM
• SQM
• HA
• SQKM
• SQFT
• A
• SQMI
• DEG
• GRD
• 400

For definitive details see:.

Adobe Supplement to the ISO 32000, BaseVersion: 1.7, ExtensionLevel: 3; Table: 8.111a, page 50.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 269, page 599.