MAP
The MAP step adjusts the pipeline at any point in a flow. It makes pipeline modifications that are independent of an INVOKE step.
Within the MAP step, you can:
Link (copy) the value of a pipeline input field to a new or existing pipeline output field.
Drop an existing pipeline input field. (Keep in mind that once you drop a field from the pipeline, it is no longer available to subsequent services in the flow.)
Assign a value to a pipeline output field.
Perform document-to-document mapping in a single view by inserting transformers.