import math

def midpoint(x1, y1, x2, y2):
Input values as degrees
Convert to radians

lat1 = math.radians(x1)
lon1 = math.radians(x2)
lat2 = math.radians(y1)
lon2 = math.radians(y2)

bx = math.cos(lat2) * math.cos(lon2 - lon1)
by = math.cos(lat2) * math.sin(lon2 - lon1)
lat3 = math.atan2(math.sin(lat1) + math.sin(lat2), \
       math.sqrt((math.cos(lat1) + bx) * (math.cos(lat1) \
       + bx) + by**2))
lon3 = lon1 + math.atan2(by, math.cos(lat1) + Bx)

return [round(math.degrees(lat3), 2), round(math.degrees(lon3), 2)]

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