Getting wrong coordinates converting UTM to lon/lat with Proj

Question

I have tried many ways to convert UTM to lon/lat, and getting always the same weird result.

Getting UTM and lon/lat for a point using GoogleEarth:

from pyproj import Proj

lon = -40.729124
lat = -20.967705

z = 24
l = 'k'
posx = 320235.13
posy = 7680455.66

myProj = Proj("+proj=utm +zone=24K, +south +ellps=WGS84 +datum=WGS84 +units=m +no_defs")

clon, clat = myProj(posx, posy, inverse=True)

print(clon, clat)

I get...

-43.534213641680765 69.17434868536577

What do I missing?

Answer 1

try "+proj=utm +zone=24 +south +datum=WGS84 +units=m +no_defs ". use epsg.io to identify the appropriate proj4 input, look at the bottom of the page.

another alternative is just use epsg code which is easier like this,

Proj('EPSG:32724')

---

alternatively using geopandas

from geopandas import GeoSeries
from shapely.geometry import Point

posx = 320235.13
posy = 7680455.66

# utm 24s is equivalent to epsg:32724
lon, lat = GeoSeries([Point(posx, posy)], crs='EPSG:32724').to_crs('epsg:4326')[0].coords[0] 

print(lon, lat)

# this prints -20.967705012999282 -40.729123995168585  

Answer 2

After trying your code I could get an error:

pyproj.exceptions.CRSError: Invalid projection: +proj=utm +zone=24K, +south +ellps=WGS84 +datum=WGS84 +units=m +no_defs +type=crs: (Internal Proj Error: proj_create: Error 1027 (Invalid value for an argument): utm: Invalid value for zone)

Which tells explicitly : "Invalid value for zone".

However, as soon as you erase K, it can be validated.

Hereafter, it is suggested to work with the Transformer class, that takes into account datum shifts.

from pyproj import CRS
from pyproj import Transformer

posx, posy = 320235.13, 7680455.66

from_crs = CRS.from_proj4("+proj=utm +zone=24 +south +ellps=WGS84 +datum=WGS84 +units=m +no_defs")
to_crs = CRS.from_epsg(4326)

proj = Transformer.from_crs(from_crs, to_crs, always_xy=True)
coordinates = proj.transform(posx, posy)

print(coordinates) #(-40.729123995168585, -20.967705012999282)