Evaluation Context

XPath also has a method for referencing relative paths from a particular node. If you have an evaluation context, or a particular starting node in a schema tree, you can specify the relative path to other elements in the tree.

For example, if your evaluation context is $GetOrderInformation/ShipName, then you can reference the sub-items of ShipName without specifying the entire path. If you wish to reference $GetOrderInformation/RequiredDate, the relative path would be ../RequiredDate. The path is relative to the evaluation context — RequiredDate is one level higher in the schema tree than the elements of ShipName.