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Is there any more news on this 'bug' as it appears to be serious or it might simply be the wording.</div>
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Example:</div>
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Project created in old version of qgis and opened in recent version. It comes up with the message about "Ballpark Transformations" and suggests installing proj-datumgrid-europe-1.5.zip to enable a better transformatoin between epsg:27700 and epsg:4326. The
project contains the OS GB1936 system and WGS84.</div>
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So I installed the relevant .gsb files in the correct directory with the other .gsb files, restarted and tried again to open the project. This time it did not come up with the message suggesting the download but instead just suggested using one of the other
transformations which are less accurate than the proper <span style="font-family:'Courier New'; color:#303030">
OSTN15_NTv2</span> transformation.</div>
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Need to know why it is doing the less accurate transformation and how to get it to do the correct transformation instead.<br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Qgis-user <qgis-user-bounces@lists.osgeo.org> on behalf of Randal Hale <rjhale@northrivergeographic.com><br>
<b>Sent:</b> 27 February 2020 17:56<br>
<b>To:</b> qgis-user@lists.osgeo.org <qgis-user@lists.osgeo.org><br>
<b>Subject:</b> [Qgis-user] Question On "BallPark Transform"</font>
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<span>CAUTION: This mail comes from outside the University. Please consider this before opening attachments, clicking links, or acting on the content.
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<p>Greetings, <br>
</p>
<p>I received an email from two users with 3.12 asking about "Ballpark Transformations" - the exact phrase was "Used a Ballpark transformation from EPSG:4326 to EPSG: 2274".
<br>
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<p>I've been able to generate the message twice by: <br>
</p>
<ul>
<li>changing the projection of a new project with no data from 4326 to 2274 <br>
</li><li>adding data with an incorrect spatial extent that I believe was in 4326 and applied to a project in 2274 (I think - I currently don't have access to that data to confirm)<br>
</li></ul>
<p>I've found mention of it here: <a class="x_moz-txt-link-freetext" href="https://qgis.org/api/classQgsCoordinateTransform.html#a16adb051fafc25058c0040a310f1606b">
https://qgis.org/api/classQgsCoordinateTransform.html#a16adb051fafc25058c0040a310f1606b
</a><br>
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<p>The expanded message in QGIS is: <br>
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<p><span></p>
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<i><b>An alternative, ballpark-only transform was used when transforming coordinates between
</b></i><i><b>EPSG:4326 - WGS 84</b></i><i><b> and </b></i><i><b>EPSG:2274 - NAD83 / Tennessee (ftUS)</b></i><i><b>. The results may not match those obtained by using the preferred operation:</b></i><i><b>
</b></i></p>
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<i><b>Possibly an incorrect choice of operation was made for transformations between these reference systems. Check the Project Properties and ensure that the selected transform operations are applicable over the whole extent of the current project.</b></i></p>
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</span>If I check the project properties there is no Datum Transformation defined after all this happens.
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<span></span>
<p></p>
<p>I'm assuming that if a project has no data and one jumps datums by changing the projection it's saying "Hey since there is no data this transformation is a "ballpark" i.e. not exact". Is there a preferred way to dealing with this after it happens?
<br>
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<p>Randy<br>
</p>
<pre class="x_moz-signature" cols="72">--
Randal Hale
<a class="x_moz-txt-link-abbreviated" href="mailto:rjhale@northrivergeographic.com">rjhale@northrivergeographic.com</a>
(p) 423.653.3611
<a class="x_moz-txt-link-freetext" href="http://www.northrivergeographic.com">http://www.northrivergeographic.com</a></pre>
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