Generating discrete fractured network (DFN) at the base of geometrical and physical characterizations of discontinuities is one the most important methods to study the discontinuity system effect on rock mass. In this paper characterizations of 639 discontinuities surveyed in powerhouse cavern of Rodbar Lorestan project have been studied by scanline and areal sampling methods. Based on the processes and corrections of bias types, one bedding and three joint sets were existed in the site. The tectonic activities and direction of principal stresses have caused differences in trace length and spacing characteristics and the probability distribution function of joint sets based on their genetic types. The calculated average trace length by scanline and areal method are very close for one joint set and for the other one the difference is 26%. The density differences between circular and rectangle sampling windows for joint sets J1 and J2 are 7% and 15%, respectively. The differences between actual and apparent intensity in circular sampling for joint sets J1 and J2 are 12% and 14%, respectively. Meanwhile, the volumetric intensity calculated by various methods have shown that the calculation of this characteristic is very difficult in the field.