1. A method of providing measuring data for a precise local positioning of a surgical catheter, comprising: recording electrophysiological potential curves at a plurality of positions of the surgical catheter in a vessel or organ by the surgical catheter; relating each recorded electrophysiological potential curve to an electric potential measurement executed by a reference catheter located in the vessel or organ; recording an x-ray image at each of the plurality of positions, each x-ray image at least partially showing the surgical catheter; marking a position of the surgical catheter in each x-ray image using markers; assigning the electrophysiological potential curves to the markers; displaying on a screen at least one of the x-ray images having at least one of the markers or displaying on the screen at least one of the recorded electrophysiological potential curves; activating the at least one marker of the displayed x-ray image or the at least one displayed electrophysiological potential curve; and querying and displaying such electrophysiological potential curve assigned to the activated marker or such x-ray image having such marker related to the activated electrophysiological potential curve, wherein different electrophysiological potential curves are displayed in different colors, and a related marker is displayed in such color corresponding to the respective electrophysiological potential curve, and wherein the different colors are determined by a color coding algorithm, the color coding algorithm based on a delay time of a signal included in the electrophysiological potential curves, the delay time of the signal calculated relative to a reference signal provided by the reference catheter.