Air navigation charts V30 (series). 20. Lat. 29° N-45° N, long. 118° W-150° W. Scale 1″ = 30 naut. m. (1:2.188.-800) at lat. 3 7° 30′, contour interval, 1,000. 2,000, 3,000, 5,000, 7.000, 9,000 and 12,000 ft.