[Proj] Differences across v4.8 and v4.9

[Joaquim Luis]

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>> The first one (between A1 and B1) is specially more troublesome because  
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>> the example provide in the cs2cs doc page
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>> (http://proj4.org/apps/cs2cs.html) that agrees with 4.8.0 and not with
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>> 4.9.2
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>> Joaquim
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>> proj
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>> Rel. 4.8.0, 6 March 2012
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>> A1
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>> echo 45.25919444444 -111.5 | cs2cs +proj=latlong +datum=NAD83 +to
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>> +proj=utm +zone=10  +datum=NAD27 -r
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>> 1402285.99      5076292.42 -0.00
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> I do get this result with proj 4.9.3 too (actually I get  
> 1402285.98	5076292.42 -0.00,
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> so a slight difference rounding), so I suspect your below 4.9.3 build  
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> without unzipping first the grids at
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> http://download.osgeo.org/proj/proj-datumgrid-1.6.zip
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> into the nad/ directory
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No I hadn't. I didn't know about those files. I build proj.4 from the  
Github repo and thought it had all necessary files.

Now I also get

pj_apply_gridshift(): used Conterminous United States
1402285.98      5076292.42 -0.00

but it still complains of not finding

pj_open_lib(ntv2_0.gsb): call  
fopen(C:\programs\compa_libs\proj4_GIT\nad\ntv2_0.gsb) - failed

which is not in the proj-datumgrid-1.6.zip file


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> You can check if grids are used with
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> echo 45.25919444444 -111.5 | PROJ_DEBUG=ON cs2cs  +proj=latlong  
> +datum=NAD83 +to  +proj=utm >+zone=10  +datum=NAD27 -r
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> You should see towards the end something like
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> NTv1 393x177: LL=(-142,40) UR=(-44,84)
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> pj_open_lib(conus): call fopen([...]/share/proj/conus) - succeeded
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> pj_apply_gridshift(): used Conterminous United States
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>> A2
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>> echo 4.897 52.371 | proj +proj=aeqd +ellps=WGS84 +units=m
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>> 384923.72       5809986.50
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> Not completely sure about that one when looking at history of
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> https://github.com/OSGeo/proj.4/commits/master/src/PJ_aeqd.c
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> Perhaps
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> https://github.com/OSGeo/proj.4/commit/2d0acd7d61374a167f532cd2851f46f63d5e09a4
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> or
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> https://github.com/OSGeo/proj.4/commit/de8d6779aaabe0c46c06b9047bc6a6a978cc0758
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>> A3
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>> echo 4.897 52.371 | proj +proj=robin +ellps=WGS84 +units=m
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>> 394576.51       5571243.64
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> I suspect the difference comes from
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> https://github.com/OSGeo/proj.4/commit/d856016ca1a178cc81c4474c0a6bbe78d106d012
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> I agree the https://github.com/OSGeo/proj.4/blob/master/NEWS don't  
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> --
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