1

According to this quite thorough answer :

Is re-projection needed from SRID 4326 (WGS 84) to SRID 4269 (NAD 83)?

the crs EPSG:4326 and EPSG:4269 are slightly different, due to a difference in one of the semi-axis of the reference ellipsoids (small difference) and also to a shift in the origin of the NAD83 Datum used in 4269.

However, when using pyproj (python 3.8.8 and pyproj 3.0.1 on windows) to project a point from EPSG:4326 to EPSG:4269, I obtain the exact same lat/lon :

from pyproj import CRS, Transformer
from shapely.geometry import Point
from shapely.ops import transform

crs_4326 = CRS("EPSG:4326")
crs_4269 = CRS("EPSG:4269")


transformer_4326_to_4269 = Transformer.from_crs(crs_from=crs_4326, crs_to=crs_4269).transform
p = Point(-118,33)  # some position in California
p1 = transform(transformer_4326_to_4269, p)


print(p)  # returns POINT (-118 33)
print(p1) # also returns POINT (-118 33) !

I am quite confused as I was expecting a (rather small) difference.

Anon_Chem
  • 29
  • 2
  • https://gis.stackexchange.com/q/304231/2856 – user2856 Mar 13 '21 at 23:15
  • I hadn't seen this link thanks. However, the answer provided is quite unsatisfactory : it says that unless you project the solution, you will not see a shift in the data, while linking to another answer which clearly states the opposite (between NAD27 to NAD83). – Anon_Chem Mar 14 '21 at 00:02
  • This doesn't explain the particular relationship between 4326 and 4269 : consider changing EPSG 4269 above to EPSG 4289 (Amersfoort datum), there will be a slight change in the lat/lon values instead of non. – Anon_Chem Mar 14 '21 at 00:03
  • 1
    I've added a bounty to the existing question to try and attract more attention. – user2856 Mar 14 '21 at 00:36
  • I've added a possible answer in https://gis.stackexchange.com/q/304231/2856 – user2856 Mar 20 '21 at 09:00

0 Answers0