1. A computer implemented method for hierarchical editing of a physical layout representation of an integrated circuit while transforming a netlist representation of the integrated circuit to the physical layout of the integrated circuit, the method comprising: creating, by the computer, a handle to a first physical shape disposed in a first level of hierarchy of the layout representation, wherein the first physical shape has a first set of coordinates in a first coordinate system associated with the first level of hierarchy; determining a transform value defining the location of the first physical shape with respect to a second coordinate system associated with a second level of hierarchy; storing the transform value via the handle in a memory disposed in the computer system; determining a second set of coordinates of the first physical shape in the second coordinate system in accordance with the transform value, and using the handle to provide an interface to the first physical shape so as to make the first physical shape appear as being in the second level of hierarchy