Abstract. Data recorded on potential gamma ray sources using Imaging Atmospheric Cherenkov Telescopes is usually dominated by the background of cosmic rays with a typical ratio of 1:1000 events. In order to obtain a sensitive measurement of a gamma ray source, an effective background suppression in the data is necessary by retaining a large fraction of gamma ray events. A set of image parameters called Hillas parameters are usually applied for gamma and cosmic ray separation using both source dependent and source independent information in the camera. The Disp analysis procedure uses the information of the shower image shape to reconstruct the position of the source on an event-by-event basis assuming that the source position lies on the major axis of the image. However, this procedure provides two source positions along the major axis of the image but does not provide information on which side of the shower image the arrival direction lies. The asymmetry charge distribution in the image contains the head and tail information of the recorded shower in the camera plane. The implementation details of Disp analysis procedure using TACTIC simulated data will be discussed in this meeting.