The projection coordinates are the same for different geographic coordinate systems

[wozaicik]

crs_4326 = CRS("WGS84")
crs_4480 = CRS(4480)
crs_4490 = CRS(4490)
crs_4547 = CRS(4547)
transformer = Transformer.from_crs(crs_4326, crs_4547)
print(transformer.transform(23, 114))
transformer = Transformer.from_crs(crs_4480, crs_4547)
print(transformer.transform(23, 114))
transformer = Transformer.from_crs(crs_4490, crs_4547)
print(transformer.transform(23, 114))
(2544537.57855209, 500000.0)
(2544537.57855209, 500000.0)
(2544537.57855209, 500000.0)
(2544537.57855209, 500000.0)
i donot understand why？the result is error that Compared to Qgis results

[snowman2]

If you look at the description of the transformer for each one, you will see the core component is the 3-degree Gauss-Kruger CM 114E. Some of the other have ballpark/null transformations in addition that seem to not have any effect:

>>> Transformer.from_crs(4326, 4547)
<Concatenated Operation Transformer: pipeline>
Description: Ballpark geographic offset from WGS 84 to China Geodetic Coordinate System 2000 + 3-degree Gauss-Kruger CM 114E
Area of Use:
- name: World
- bounds: (-180.0, -90.0, 180.0, 90.0)
>>> Transformer.from_crs(4480, 4547)
<Concatenated Operation Transformer: pipeline>
Description: Null geographic offset from China Geodetic Coordinate System 2000 (geog3D) to China Geodetic Coordinate System 2000 (geog2D) + 3-degree Gauss-Kruger CM 114E
Area of Use:
- name: China - onshore and offshore.
- bounds: (73.62, 16.7, 134.77, 53.56)
>>> Transformer.from_crs(4490, 4547)
<Conversion Transformer: pipeline>
Description: 3-degree Gauss-Kruger CM 114E
Area of Use:
- name: Between 112°30'E and 115°30'E, northern hemisphere.
- bounds: (112.5, 0.0, 115.5, 84.0)

You can confirm the transformations are all the same in PROJ by looking at the pipeline:

>>> Transformer.from_crs(4326, 4547).to_proj4()
'+proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +proj=tmerc +lat_0=0 +lon_0=114 +k=1 +x_0=500000 +y_0=0 +ellps=GRS80 +step +proj=axisswap +order=2,1'
>>> Transformer.from_crs(4480, 4547).to_proj4()
'+proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +proj=tmerc +lat_0=0 +lon_0=114 +k=1 +x_0=500000 +y_0=0 +ellps=GRS80 +step +proj=axisswap +order=2,1'
>>> Transformer.from_crs(4490, 4547).to_proj4()
'+proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +proj=tmerc +lat_0=0 +lon_0=114 +k=1 +x_0=500000 +y_0=0 +ellps=GRS80 +step +proj=axisswap +order=2,1'