1. In a mapping tool graphical user interface, a method of creating a mapping, comprising: displaying a graphical representation of a source object including a source tree structure having a source root node, a source record node, and a source field node in a source screen region; displaying a graphical representation of a target object including a target tree structure having a target root node, a target record node, and a target field node in a target screen region; creating a mapping between the graphical representation of the source object and the graphical representation of the target object in a mapping screen region located between the source and target screen regions using graphical mapping indicia; indenting the field nodes toward the mapping screen region in hierarchical fashion from the record nodes; and indenting the record nodes toward the mapping screen region in hierarchical fashion from the root nodes.