In this paper, a computer routine, POLAN, was used to convert an ionogram recorded at Cleary, Alaska to many electron density true height profiles by specifying various values of MODE, START and VALLEY parameters. These profiles are then compared with that measured by the Chatanika incoherent scatter radar. This comparison allows us to evaluate the difference of the electron density profiles respectively derived by using ionospheric sounding and incoherent backscatter techniques and to investigate the existing true height analysis methods.