deg_min_sec.py

# =========================================================
# calculate the number of feet and meters in a second of
# arc given the earth's circumference
# ---------------------------------------------------------
# the calculations assume the earth is a perfect sphere
# (the earth is a pear shaped oblate spheroid)
# =========================================================

# -- constants

CIR = 24901.0          # circumference of earth in miles
FML = 5280.0           # feet per mile
FMT = 3.28084          # feet per meter

DEG = 360              # degrees in circle
MIN = 60               # minutes per degree
SEC = 60               # seconds per minute

# --- calculate

cf  = CIR * FML        # circumference of earth in feet

cs  = DEG * MIN * SEC  # seconds in a circle

ft = cf / cs           # feet per second of arc
mt = ft / FMT          # meters per second of arc

# -- display data

print('-- A Second of Arc (Earth Circumference) --')
print('   feet   = {}'.format(ft))
print('   meters = {}'.format(mt))