The calculated altitude ("Hc") is compared to the observed altitude ("Ho", sextant altitude ("Hs") corrected for various errors). The difference between "Hc" and "Ho" is called "intercept" and is the observer's distance from the assumed position. The resulting line of position ("LOP") is a small segment of the circle of equal altitude, and is represented by a straight line perpendicular to the azimuth of the celestial body. When plotting the small segment of this circle on a chart it is drawn as a straight line, the resulting tiny errors are too small to be significant.