[gdal-dev] Issue with Custom Transformation Pipeline in GDALReprojectImage

[Even Rouault]

>
> Regarding the pipeline, it could be a bad copy-paste or garbled by 
> ChatGPT 😀.

I wouldn't trust ChatGPT to come with geodesic-relevant pipelines... If 
you aren't really sure about what you are doing, you'd better let PROJ 
infer a reasonable pipeline.

I'm also questioning the use of the grid Slovakia_JTSK03_to_JTSK to go 
from JTSK03 to WGS 84, since the shift between JTSK03 and JTSK is really 
small compared to the one between JTSK03 and ETRS89

$ echo 48 20 0 | PROJ_NETWORK=ON cs2cs -d 8 "S-JTSK [JTSK03]" "S-JTSK"   
(uses the grid)
48.00000488    19.99999497 0.00000000

$ echo 48 20 0 | PROJ_NETWORK=ON cs2cs -d 8 "S-JTSK [JTSK03]" "ETRS89"  
(uses an Helmert transformation)
47.99966528    19.99834773 0.00000000

$ echo 48 20 0 | PROJ_NETWORK=ON cs2cs -d 8 "S-JTSK [JTSK03]" "WGS 84"  
(uses the same Helmert transformation as above, assuming WGS84 ~= ETRS89)
47.99966527    19.99834773 0.00000000

And more generally, people posting issues/questions written partially or 
totally written by generative "IA" should really mention it to set 
expectations to readers

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