<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Tue, Mar 17, 2015 at 9:53 PM, Even Rouault <span dir="ltr"><<a href="mailto:even.rouault@spatialys.com" target="_blank">even.rouault@spatialys.com</a>></span> wrote:<br><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">As most of the "heavy" grids are not directly distributed with proj, it might be<br>
tricky to propose a reasonable +nadgrids parameter. Although we could use the @<br>
syntax to make their presence optional. </blockquote><div><br></div><div>What is the "@ syntax"? <br></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">But there's currently no way of doing<br>
the association between a datum and corresponding grids when the "raw" CSV files<br>
are processed in the gcs.csv/pcs.csv. Perhaps something similar to<br>
<a href="http://svn.osgeo.org/metacrs/geotiff/trunk/libgeotiff/csv/datum_shift_pref.csv" target="_blank">http://svn.osgeo.org/metacrs/geotiff/trunk/libgeotiff/csv/datum_shift_pref.csv</a><br>
could be used.<br></blockquote><div><br></div><div>I'm still unclear as to how <a href="http://epsg.org">epsg.org</a> addresses grid shifts. I randomly surfed thru the files in <a href="http://svn.osgeo.org/metacrs/geotiff/trunk/libgeotiff/csv/datum_shift_pref.csv" target="_blank">http://svn.osgeo.org/metacrs/geotiff/trunk/libgeotiff/csv/</a> and found no clues. It seems like it would be nice to enhance the processing of the <a href="http://epsg.org">epsg.org</a> source definitions to reference grid shift files if possible. By "if possible" I mean if there is sufficient information in the <a href="http://epsg.org">epsg.org</a> source definitions to do that. If not, then I agree that something like datum_shift_pref.csv would be good.</div><div><br></div><div>Thanks,</div><div>Rich</div><div><br></div><div><br></div><div> </div></div>
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