Its Survey_ID and Survey_ID_Ref class members are used to identify the relationship for all geographic features created by a particular survey project .
SSDMSurveryObject is the most important abstract class in SSDM .
SSDM 's Survey_ID and Survey_ID_Ref class members are used to identify the relationship for all geographic features created by a particular survey project .
SSDMSurveryObject is the most important abstract class in SSDM .