[BREAKING] Hermert: add +convention=position_vector/coordinate_frame, forbids +transpose (fixes #1091)

As identified in #1091, Helmert implementation in PROJ 5.0 and 5.1 is confusing.
It happens that by default it used the coordinate_frame convention, contrary to
the position_vector convention used traditionaly for +towgs84. The documentation
of Helmert was also wrongly specifying that the default convention was
position_vector.

This commit:
- bans the confusing +transpose parameter
- removes the concept of a default convention, since in practice both are
  equally found, and requires +convention as soon as a rotational term parameter
  is present.
  For translation only, convention is ignored and optional, as having no effect.
- fixes all the identified uses of proj=helmert in code, doc and tests

This is obviously a breaking change:
- users will have to adapt their pipeline expressions
- in particular, init files that would use helmert must be adapted

However, as designed, the break will be explicit, and not silent.

1 files changed, 25 insertions, 25 deletions

diff --git a/nad/ITRF2008 b/nad/ITRF2008
index 2d730d6e..33964d9d 100644
--- a/nad/ITRF2008
+++ b/nad/ITRF2008
@@ -1,27 +1,27 @@
 # ITRF2008 params are in mm/year, PJ_helmert uses m/year
 <metadata> +version=1.0.0 +origin=http://itrf.ign.fr/doc_ITRF/Transfo-ITRF2008_ITRFs.txt +lastupdate=2017-07-26
 
-<ITRF2005> +proj=helmert +x=-0.002 +y=-0.0009 +z=-0.0047 +s=0.00094 +dx=0.0003 +t_epoch=2000.0 +transpose
+<ITRF2005> +proj=helmert +x=-0.002 +y=-0.0009 +z=-0.0047 +s=0.00094 +dx=0.0003 +t_epoch=2000.0 +convention=position_vector
 
-<ITRF2000> +proj=helmert +x=-0.0019 +y=-0.0017 +z=-0.0105 +s=0.00134  +dx=0.0001 +dy=0.0001 +dz=-0.0018 +ds=0.00008  +t_epoch=2000.0 +transpose
+<ITRF2000> +proj=helmert +x=-0.0019 +y=-0.0017 +z=-0.0105 +s=0.00134  +dx=0.0001 +dy=0.0001 +dz=-0.0018 +ds=0.00008  +t_epoch=2000.0 +convention=position_vector
 
-<ITRF97> +proj=helmert +x=0.0048 +y=0.0026 +z=-0.0332 +s=0.00292 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +transpose
+<ITRF97> +proj=helmert +x=0.0048 +y=0.0026 +z=-0.0332 +s=0.00292 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +convention=position_vector
 
-<ITRF96> +proj=helmert +x=0.0048 +y=0.0026 +z=-0.0332 +s=0.00292 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +transpose
+<ITRF96> +proj=helmert +x=0.0048 +y=0.0026 +z=-0.0332 +s=0.00292 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +convention=position_vector
 
-<ITRF94> +proj=helmert +x=0.0048 +y=0.0026 +z=-0.0332 +s=0.00292 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +transpose
+<ITRF94> +proj=helmert +x=0.0048 +y=0.0026 +z=-0.0332 +s=0.00292 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +convention=position_vector
 
-<ITRF93> +proj=helmert +x=-0.024 +y=0.0024 +z=-0.00386 +s=0.00341 +rx=-0.00171 +ry=-0.00148 +rz=-0.0003 +dx=-0.0028 +dy=-0.0001 +dz=-0.0024 +ds=0.00009 +drx=-0.00011 +dry=-0.00019 +drz=0.00007 +t_epoch=2000.0 +transpose
+<ITRF93> +proj=helmert +x=-0.024 +y=0.0024 +z=-0.00386 +s=0.00341 +rx=-0.00171 +ry=-0.00148 +rz=-0.0003 +dx=-0.0028 +dy=-0.0001 +dz=-0.0024 +ds=0.00009 +drx=-0.00011 +dry=-0.00019 +drz=0.00007 +t_epoch=2000.0 +convention=position_vector
 
-<ITRF92> +proj=helmert +x=0.0128 +y=0.0046 +z=-0.0412 +s=0.00221 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +transpose
+<ITRF92> +proj=helmert +x=0.0128 +y=0.0046 +z=-0.0412 +s=0.00221 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +convention=position_vector
 
-<ITRF91> +proj=helmert +x=0.0248 +y=0.0186 +z=-0.0472 +s=0.00361 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +transpose
+<ITRF91> +proj=helmert +x=0.0248 +y=0.0186 +z=-0.0472 +s=0.00361 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +convention=position_vector
 
-<ITRF90> +proj=helmert +x=0.0228 +y=0.0146 +z=-0.0632 +s=0.00391 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +transpose
+<ITRF90> +proj=helmert +x=0.0228 +y=0.0146 +z=-0.0632 +s=0.00391 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +convention=position_vector
 
-<ITRF89> +proj=helmert +x=0.0278 +y=0.0386 +z=-0.1012 +s=0.00731 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +transpose
+<ITRF89> +proj=helmert +x=0.0278 +y=0.0386 +z=-0.1012 +s=0.00731 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +convention=position_vector
 
-<ITRF88> +proj=helmert +x=0.0228 +y=0.0026 +z=-0.1252 +s=0.01041 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +transpose
+<ITRF88> +proj=helmert +x=0.0228 +y=0.0026 +z=-0.1252 +s=0.01041 +rz=0.00006 +dx=0.0001 +dy=-0.0005 +dz=-0.0032 +ds=0.00009 +drz=0.00002 +t_epoch=2000.0 +convention=position_vector
 
 
 # ITRF2008 Plate Motion Model parameters
@@ -32,30 +32,30 @@
 # J. Geophys. Res., 117, B07402, doi:10.1029/2011JB008930.
 
 
-<AMUR> +proj=helmert +drx=-0.000190 +dry=-0.000442 +drz=0.000915
+<AMUR> +proj=helmert +drx=-0.000190 +dry=-0.000442 +drz=0.000915 +convention=coordinate_frame
 
-<ANTA> +proj=helmert +drx=-0.000252 +dry=-0.000302 +drz=0.000643
+<ANTA> +proj=helmert +drx=-0.000252 +dry=-0.000302 +drz=0.000643 +convention=coordinate_frame
 
-<ARAB> +proj=helmert +drx=0.001202 +dry=-0.000054 +drz=0.001485
+<ARAB> +proj=helmert +drx=0.001202 +dry=-0.000054 +drz=0.001485 +convention=coordinate_frame
 
-<AUST> +proj=helmert +drx=0.001504 +dry=0.001172 +drz=0.001228
+<AUST> +proj=helmert +drx=0.001504 +dry=0.001172 +drz=0.001228 +convention=coordinate_frame
 
-<CARB> +proj=helmert +drx=0.000049 +dry=-0.001088 +drz=0.000664
+<CARB> +proj=helmert +drx=0.000049 +dry=-0.001088 +drz=0.000664 +convention=coordinate_frame
 
-<EURA> +proj=helmert +drx=-0.000083 +dry=0.000534 +drz=0.000750
+<EURA> +proj=helmert +drx=-0.000083 +dry=0.000534 +drz=0.000750 +convention=coordinate_frame
 
-<INDI> +proj=helmert +drx=0.001232 +dry=0.000303 +drz=0.001540
+<INDI> +proj=helmert +drx=0.001232 +dry=0.000303 +drz=0.001540 +convention=coordinate_frame
 
-<NAZC> +proj=helmert +drx=-0.000330 +dry=-0.001551 +drz=0.001625
+<NAZC> +proj=helmert +drx=-0.000330 +dry=-0.001551 +drz=0.001625 +convention=coordinate_frame
 
-<NOAM> +proj=helmert +drx=0.000035 +dry=-0.000662 +drz=0.0001
+<NOAM> +proj=helmert +drx=0.000035 +dry=-0.000662 +drz=0.0001 +convention=coordinate_frame
 
-<NUBI> +proj=helmert +drx=0.000095 +dry=-0.000598 +drz=0.000723
+<NUBI> +proj=helmert +drx=0.000095 +dry=-0.000598 +drz=0.000723 +convention=coordinate_frame
 
-<PCFC> +proj=helmert +drx=0.000411 +dry=0.001036 +drz=-0.002166
+<PCFC> +proj=helmert +drx=0.000411 +dry=0.001036 +drz=-0.002166 +convention=coordinate_frame
 
-<SOAM> +proj=helmert +drx=-0.000243 +dry=-0.000311 +drz=-0.000154
+<SOAM> +proj=helmert +drx=-0.000243 +dry=-0.000311 +drz=-0.000154 +convention=coordinate_frame
 
-<SOMA> +proj=helmert +drx=-0.000080 +dry=-0.000745 +drz=0.000897
+<SOMA> +proj=helmert +drx=-0.000080 +dry=-0.000745 +drz=0.000897 +convention=coordinate_frame
 
-<SUND> +proj=helmert +drx=0.000047 +dry=-0.001 +drz=0.000975
+<SUND> +proj=helmert +drx=0.000047 +dry=-0.001 +drz=0.000975 +convention=coordinate_frame