DOCUMENT_UNIT

DOCUMENT_UNIT_UNDEF	Undefined.
DOCUMENT_UNIT_KM	Kilometer.
DOCUMENT_UNIT_M	Meter.
DOCUMENT_UNIT_CM	Centimeter.
DOCUMENT_UNIT_MM	Millimeter.
DOCUMENT_UNIT_MICRO	Micrometer.
DOCUMENT_UNIT_MILE	Mile.
DOCUMENT_UNIT_YARD	Yard.
DOCUMENT_UNIT_FOOT	Foot.
DOCUMENT_UNIT_INCH	Inch.