CRS to Lat/Lon with only base packages

crs_lat_lon_convert.py

import math

def utmToLatLng(utmZone, mean_easting, mean_northing, northernHemisphere):
    utmZone            = int(utmZone)
    mean_easting       = float(mean_easting)
    mean_northing      = float(mean_northing)
    northernHemisphere = int(northernHemisphere)
    
    if not northernHemisphere:
        mean_northing = 10000000 - mean_northing
 
    a = 6378137
    e = 0.081819191
    e1sq = 0.006739497
    k0 = 0.9996
 
    arc = mean_northing / k0
    mu = arc / (a * (1 - math.pow(e, 2) / 4.0 - 3 * math.pow(e, 4) / 64.0 - 5 * math.pow(e, 6) / 256.0))
 
    ei = (1 - math.pow((1 - e * e), (1 / 2.0))) / (1 + math.pow((1 - e * e), (1 / 2.0)))
 
    ca = 3 * ei / 2 - 27 * math.pow(ei, 3) / 32.0
    cb = 21 * math.pow(ei, 2) / 16 - 55 * math.pow(ei, 4) / 32
    cc = 151 * math.pow(ei, 3) / 96
    cd = 1097 * math.pow(ei, 4) / 512
    phi1 = mu + ca * math.sin(2 * mu) + cb * math.sin(4 * mu) + cc * math.sin(6 * mu) + cd * math.sin(8 * mu)
 
    n0 = a / math.pow((1 - math.pow((e * math.sin(phi1)), 2)), (1 / 2.0))
 
    r0 = a * (1 - e * e) / math.pow((1 - math.pow((e * math.sin(phi1)), 2)), (3 / 2.0))
    fact1 = n0 * math.tan(phi1) / r0
 
    a1 = 500000 - mean_easting
    dd0 = a1 / (n0 * k0)
    fact2 = dd0 * dd0 / 2
 
    t0 = math.pow(math.tan(phi1), 2)
    Q0 = e1sq * math.pow(math.cos(phi1), 2)
    fact3 = (5 + 3 * t0 + 10 * Q0 - 4 * Q0 * Q0 - 9 * e1sq) * math.pow(dd0, 4) / 24
 
    fact4 = (61 + 90 * t0 + 298 * Q0 + 45 * t0 * t0 - 252 * e1sq - 3 * Q0 * Q0) * math.pow(dd0, 6) / 720
 
    lof1 = a1 / (n0 * k0)
    lof2 = (1 + 2 * t0 + Q0) * math.pow(dd0, 3) / 6.0
    lof3 = (5 - 2 * Q0 + 28 * t0 - 3 * math.pow(Q0, 2) + 8 * e1sq + 24 * math.pow(t0, 2)) * math.pow(dd0, 5) / 120
    _a2 = (lof1 - lof2 + lof3) / math.cos(phi1)
    _a3 = _a2 * 180 / math.pi
 
    latitude = 180 * (phi1 - fact1 * (fact2 + fact3 + fact4)) / math.pi
 
    if not northernHemisphere:
        latitude = -latitude
 
    longitude = ((utmZone > 0) and (6 * utmZone - 183.0) or 3.0) - _a3
 
    return (latitude, longitude)

def process(row):
    # In 'cell' mode, the process function must return
    # a single cell value for each row,
    # which will be affected to a new column.
    # The 'row' argument is a dictionary of columns of the row
    lat_lon = utmToLatLng(row["utmZone"], row["mean_easting"], row["mean_northing"], row["northernHemisphere"])
    return lat_lon