[Proj] Pipeline +init files, inverse

stevejking stevejking at talktalk.net
Thu Feb 22 17:02:19 EST 2018

Hi Kristian & Thomas,

I've tested reversing a pipeline, Using test coordinates -3 55 100, with
RC4, and the methods you've both described in this thread. On Windows 7.
Referencing Kristian's 3 cases:

case 1) do an inverse with cct
eg. cct -I +init=OSGBtrans:7709-3D
Works as expected, but is case sensitive, it must be capital -I as in
Thomas' reply.
-i generates error
Invalid option "i"

case 2) Init file Global +inv flag before the first + step
eg. <case2>    -t0 +proj=pipeline +inv +step ....

generates error
# Record 0 TRANSFORMATION ERROR: -3 55 100 
 <invalid x or y>

case 3) Init file reverse entry that self-references the init file, 
eg. <7709-3D_reverse>  +proj=pipeline +step +init=transforms:7709-3D +inv

generates error
cct: Bad transformationarguments - (malformed pipeline)
	'cct - h' for help

The init file and gridfiles can be found here:


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