include substantially any procedure on any surface apparatus 20 is controlled by a system processing unit pu 46 which is located in an operating console 48 of the apparatus pu 46 is in communication with a graphics processor gp 50 and with a tracking module 52 the functions of which are described below pu 46 is typically also in communication with other modules used for the procedure such as an ablation module and an irrigation module but for simplicity such modules are not shown in fig1 console 48 comprises controls 54 which are used by professional 30 to communicate with the processing unit typically prior to performing the procedure surface 22 is mapped and the mapping is assumed to be performed by professional 30 in order to perform the mapping a probe 60 may be configured to have a location sensor 62 at its distal end the location sensor being in communication with pu 46 so that signals from the sensor enable the processing unit to determine the location of the sensor sensor 62 may use any method for determining its location known in the art for example sensor 62 may comprise one or more coils and pu 46 may use a magnetic tracking method wherein magnetic transmitters 64 external to patient 28 generate signals in the coils the processing unit may use a tracking module such as tracking module 52 to convert the signals to location coordinates in a three dimensional 3d frame of reference.