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<p>Simon,</p>
<br>
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<div>We do not currently redistribute anything from the separate
<b>proj-data</b> bundle, only the basic set of files that end
up in <b>.../share</b> from a PROJ make/install (<b>proj.db</b>
and about 15 others, e.g. <b>nad83</b>)</div>
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Well, hopefully you don't need to do accurate datum transformations
;-)<br>
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<div>This perhaps dates from when the full set of files was
included in the main bundle, but that is before my time, and
obviously they have been split out by you into a separate
bundle for quite some time now, presumably because of their
size.</div>
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yes<br>
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cite="mid:CAJf0KTQjxv9sH6oLL_7r+UZamB4ALot8w9omG9-TgW9x4ZeUEA@mail.gmail.com">
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<div>We have never had any issues (that we know of!) with
failing to interpret client data files, so evidently PROJ
manages quite happily without the additional files from the
<b>proj-data</b> bundle but perhaps we should be
redistributing those as well?</div>
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<p>PROJ will never error out about missing grid files by default,
unless you set PROJ_ONLY_BEST_DEFAULT=YES ( Cf
<a class="moz-txt-link-freetext" href="https://proj.org/en/9.3/apps/cs2cs.html#index-0">https://proj.org/en/9.3/apps/cs2cs.html#index-0</a>) , or equivalent
setting through proj.ini or the API (accessible
from OGRCoordinateTransformationOptions::SetOnlyBest () in GDAL:
<a class="moz-txt-link-freetext" href="https://gdal.org/doxygen/structOGRCoordinateTransformationOptions.html#a77fffa9f5f421c21c9104f6ba03885a5">https://gdal.org/doxygen/structOGRCoordinateTransformationOptions.html#a77fffa9f5f421c21c9104f6ba03885a5</a>
, or <span class="w"></span><span class="sig-name descname"><span
class="n"><span class="pre"><span class="highlighted">OCTCoordinateTransformationOptionsSetOnlyBest</span></span></span></span><span
class="sig-paren">():
<a class="moz-txt-link-freetext" href="https://gdal.org/api/ogr_srs_api.html#_CPPv445OCTCoordinateTransformationOptionsSetOnlyBest35OGRCoordinateTransformationOptionsHb">https://gdal.org/api/ogr_srs_api.html#_CPPv445OCTCoordinateTransformationOptionsSetOnlyBest35OGRCoordinateTransformationOptionsHb</a></span>)
.</p>
<p>If a grid is missing, in the default mode (only_best=no)n PROJ
will fallback to whatever other less precise transformations it
has, or do a "ballpark" transformation (no-op) in the worse case,
which can be off by several tens of meters or more.</p>
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<div>If so, do we just combine the two sets of files into the
same <b>PROJ_DATA</b> directory?</div>
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<p>Yes, you can have proj.db and the grids in the same directory. Or
have different directories and mention them in PROJ_DATA using ';'
separator on Windows, or ':' on Unix-like systems. (same
convention as PATH). Cf
<a class="moz-txt-link-freetext" href="https://proj.org/en/9.3/usage/environmentvars.html#envvar-PROJ_DATA">https://proj.org/en/9.3/usage/environmentvars.html#envvar-PROJ_DATA</a><br>
</p>
<p><br>
</p>
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<div>Forgive me if there is documentation on this specific
topic which I have missed.<br>
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<div>Finally, is the latest <b>proj-data-1.16</b> compatible
with PROJ 9.3.0 (which we have frozen on for our latest
dependencies update) or must we use the previous 1.14 from
June? ...</div>
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<p>Yes, that should work. Only new content has been added<br>
</p>
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<div>and what happened to 1.15? :)</div>
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<p>proj-data 1.15 was released together with 9.3.0, and proj-data
1.14 with proj 9.2.1</p>
<p>Even</p>
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<pre class="moz-signature" cols="72">--
<a class="moz-txt-link-freetext" href="http://www.spatialys.com">http://www.spatialys.com</a>
My software is free, but my time generally not.</pre>
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