[PROJ] PROJ 6.0.0 cs2cs: cannot instantiate source coordinate system - program abnormally terminated

[Even Rouault]

Jochem,

> 
> Soon we will publish a new NTv2 and Vdatum grids and new 7 parameters for
> EPSG:: 7415 to EPSG:: 4937.

Ah, you didn't mention that there was a EPSG code for the +proj=sterea... 
definition. Sorry I don't know the EPSG database by heart (yet...) :-)

So if you do 
$ projinfo -s EPSG:7415 -t EPSG:4937

you'll get (with PROJ master or the 6.0 branch with a fix I did a few days 
ago)


Candidate operations found: 10
-------------------------------------
Operation n°1:

unknown id, Inverse of RD New + Amersfoort to ETRS89 (7) + Inverse of ETRS89 
to NAP height (1), 0.011 m, Netherlands - onshore, at least one grid missing

PROJ string:
+proj=pipeline +step +inv +proj=sterea +lat_0=52.1561605555556 
+lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel 
+step +proj=hgridshift +grids=rdtrans2008.gsb +step +proj=vgridshift 
+grids=naptrans2008.gtx +multiplier=1 +step +proj=unitconvert +xy_in=rad 
+xy_out=deg +step +proj=axisswap +order=2,1

-------------------------------------
Operation n°2:

unknown id, Inverse of RD New + Amersfoort to ETRS89 (3) + Inverse of ETRS89 
to NAP height (1), 0.51 m, Netherlands - onshore, at least one grid missing

PROJ string:
+proj=pipeline +step +inv +proj=sterea +lat_0=52.1561605555556 
+lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel 
+step +proj=push +v_3 +step +proj=cart +ellps=bessel +step +proj=helmert 
+x=565.2369 +y=50.0087 +z=465.658 +rx=0.406857330322398 +ry=-0.350732676542563 
+rz=1.8703473836068 +s=4.0812 +convention=coordinate_frame +step +inv 
+proj=cart +ellps=GRS80 +step +proj=pop +v_3 +step +proj=vgridshift 
+grids=naptrans2008.gtx +multiplier=1 +step +proj=unitconvert +xy_in=rad 
+xy_out=deg +step +proj=axisswap +order=2,1

etc etc.


So basically this works out of the box, applying both horizontal and vertical 
grids when they are available.


> So I wouldlike to know how to avoid that it is
> unclear to Proj.

If the new data is added in the EPSG registry as it was for the current one, 
there shouldn't be any issue.

 
> By the way, ETRS89 (e.g. EPSG:4258) is bound to ITRS en WGS84  is linked to
> ITRS too.

EPSG has also a direct transformation between ETRS89 and WGS84 (EPSG:1149), 
which is a null geocentric translation, with a accuracy of 1m.

What I mean is that PROJ currently lacks a special processing for the case 
when transforming between CRS, where one has a towgs84/nadgrids clause and the 
other one is a EPSG code. I've filed this as
https://github.com/OSGeo/proj.4/issues/1388

Even

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