Figure 10. Leapfrog method.
B remains at the first field station. When altimeter A reaches the second field station, both instruments are again read
d. After completing the procedure described in c above, the difference in elevation readings are corrected, and
the correct elevation for the second field station is determined with respect to the first field station.
e. The altimeters are then brought to the second field station and a reading is taken with both instruments. After
this comparison, altimeter B advances to the third field station, and altimeter A leapfrogs to the fourth field station. Again
the altimeters are brought together at the fourth field station, and compared. This procedure is repeated until all points for
which coverage is desired have been traversed.