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<p>Reposted from
<a class="moz-txt-link-freetext" href="https://gis.stackexchange.com/questions/410874/mapserver-7-4-3-poor-projection-from-british-national-grid-epsg-27700-to-web">https://gis.stackexchange.com/questions/410874/mapserver-7-4-3-poor-projection-from-british-national-grid-epsg-27700-to-web</a><br>
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<p>We have PostGIS data in BNG and are displaying it over Google
satellite imagery.</p>
<p>This worked fine previously - using a Ubuntu server running
18.04, with MapServer 7.0.7, GDAL 2.2.3, proj 4.9.3.</p>
<p>This server is long out of date and we have a new one running
20.02, with MapServer 7.4.3, GDAL 3.0.4 and proj 6.3.1. However
this is projecting the BNG layers incorrectly (~200m ESE).</p>
<p>This appears to be similar to the issue reported at <a
href="https://github.com/OSGeo/gdal/issues/3695" rel="nofollow
noreferrer">https://github.com/OSGeo/gdal/issues/3695</a>
although that claims the problem only arose after proj 7.2.1</p>
<p>I have installed the updated transform
OSTN15_NTv2_OSGBtoETRS.gsb but this had no effect.</p>
<p>Is there a way to update the transforms used by MapServer or
get MapServer to pass the transformation to PostGIS ?</p>
<p>Thanks</p>
<p>Ben<br>
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