The authors present scanning gate microscopy (SGM) measurements of an in-plane gated open quantum dot and relate structures within the measurement to a theoretical calculation of the change in conductance in a similar dot. The dot was fabricated in GaAs/AlGaAs. Electron beam lithography and wet etching were used to isolate the two dimensional electron gas and form the device geometry. The SGM image was then high-pass filtered to show both classical and quantum behavior and similarities to a calculated structure are suggested. (C) American Vacuum Society.