About Mapping Services › Manipulate and Extract Data

Manipulate and Extract Data

Data in an MDO is manipulated using the &ASSIGN statement. There are two major operand forms on the &ASSIGN statement; an MDO stem name, and a compound name.

Stem Name: MDO=vvv

Compound Name: MDO=aaa.bbb.ccc

The stem name is used to refer to the entire data portion of an MDO. An MDO does not have to have a map attached to it to be referenced by its stem.

The compound name is used to refer to a structure within the MDO. A map must be attached to the MDO for this type of reference, otherwise NCL will not be able to locate the structure. (NCL cannot make sense of the data without a map.)

The &ASSIGN verb is useful when extracting individual components in an MDO into NCL tokens.