[PROJ] Different behaviour between 9.7.1 and 9.8.0

[Javier Jimenez Shaw]

Hi

This change in behaviour is a surprise to me. I would like to know what
changed (I know the ETRS89 datum ensemble, but I was not expecting this
consequence)

Note: I do not want to change it, just to understand it.

Context: Going from EPSG:4258 (--3d) to EPSG:5514+8357 is using
both cz_cuzk_CR-2005.tif and cz_cuzk_table_-y-x_3_v1710.tif in 9.7.1 and
9.8.0

The difference is going from EPSG:4326 (--3d) to EPSG:5514+8357. In 9.7.1
it is not using cz_cuzk_table_-y-x_3_v1710.tif, but in 9.8.0 it does. (both
use cz_cuzk_CR-2005.tif)

What changed? PROJ, EPSG, both?

Thank you.
Javier

PROJ 9.8.0:
PROJ_NETWORK=ON ./proj_9.8.0/bin/projinfo EPSG:4326 EPSG:5514+8357 --3d
--spatial-test intersects --bbox 15,50,15.1,50.1 -o proj | head -n 40
Candidate operations found: 12
-------------------------------------
Operation No. 1:

unknown id, Inverse of ETRS89-CZE [2007] to WGS 84 (1) + ETRS89-CZE [2007]
to Baltic 1957 height (2) + Inverse of S-JTSK/05 to ETRS89-CZE [2007] (1) +
Modified Krovak East North (Greenwich) + Inverse of S-JTSK / Krovak East
North (EPSG:5514) to S-JTSK/05 / Modified Krovak East North (EPSG:5516) +
Inverse of Krovak East North (Greenwich) + Krovak East North (Greenwich),
1.065 m, Czechia.

... pipeline omitted. It uses cz_cuzk_CR-2005.tif
and cz_cuzk_table_-y-x_3_v1710.tif

PROJ 9.7.1:
PROJ_NETWORK=ON ./proj_9.7.1/bin/projinfo EPSG:4326 EPSG:5514+8357 --3d
--spatial-test intersects --bbox 15,50,15.1,50.1 -o proj | head -n 40
Candidate operations found: 7
-------------------------------------
Operation No. 1:

unknown id, Inverse of ETRS89 to WGS 84 (1) + ETRS89 to Baltic 1957 height
(2) + Inverse of S-JTSK to ETRS89 (1) + Krovak East North (Greenwich), 2.03
m, Czechia.

... pipeline omitted. It only uses cz_cuzk_CR-2005.tif


As a reference, from EPSG:4258 it doing this

PROJ_NETWORK=ON ./proj_9.8.0/bin/projinfo EPSG:4258 EPSG:5514+8357 --3d
--spatial-test intersects --bbox 15,50,15.1,50.1 -o proj | head -n 40
Candidate operations found: 10
-------------------------------------
Operation No. 1:

PROJ:ETRS89_3D_TO_S_JTSK_E_N_BALTIC_HEIGHT, ETRS89 to S-JTSK / Krovak East
North + Baltic 1957 height, 0.05 m, Czechia.

... pipeline omitted. It uses cz_cuzk_CR-2005.tif
and cz_cuzk_table_-y-x_3_v1710.tif
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