[PROJ] [PROJ 6.0.0] Different behaviors for creating a transformation of type EPSG:9616

[Even Rouault]

On mardi 30 avril 2019 17:53:13 CEST Didier Richard wrote:
> Ok, in that case, two more questions :
> 
> 1.- why not returning a PROJ_OBJ_LIST for proj_create_crs_to_crs to get a
> clearer API (and let the user choose amongst transformations) ?

To be honest, the new behaviour of having several candidate coordinate 
operations is a late addition. Initially, it picked up only one, but that was 
not ideal.
Another reason is that want proj_create_crs_to_crs() to remain the "easy" way 
of using the PROJ API, so returning a PJ* object directly usable by 
proj_trans() and friends, so it is not a bad thing that this complexity 
remains hidden from the user point of view.

> 
> 2.- how to get the inner projections (proj_crs_get_coordoperation does not
> seem the right one) ?

Basically proj_create_crs_to_crs() is a high level function over 
proj_create_operations(). So if you need fine grained control of which 
coordinate operation you want to use exactly, use proj_create_operations()

Even

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