When selecting the initial sources (up to about 3/4 of the total) in a geodetic sequence, SCHED tries to find one that are especially low or high at some stations. GEOHIEL sets the lower bound of the region considered to be high. The related parameter GEOLOWEL sets the upper bound to the ``low'' region. The default GEOHIEL of 40 degrees has a SecZ of 1.55. Going higher increases slew times without all that much gain in SecZ.