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<p>Nyall had requested I submit a bug report...which I forgot
about....until now soooo ->
<a class="moz-txt-link-freetext" href="https://github.com/qgis/QGIS/issues/34983">https://github.com/qgis/QGIS/issues/34983</a> <br>
</p>
<p><br>
</p>
<p>I added your explanation as a comment to the original email. <br>
</p>
<p><br>
</p>
<p>Randy<br>
</p>
<p><br>
</p>
<p>I added your message as a comment <br>
</p>
<div class="moz-cite-prefix">On 3/10/20 2:09 PM, Michael.Dodd wrote:<br>
</div>
<blockquote type="cite"
cite="mid:LNXP265MB1066A03BDDBD1BF85873D41BB0FF0@LNXP265MB1066.GBRP265.PROD.OUTLOOK.COM">
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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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<br>
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<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
Example:</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
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>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
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>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
Need to know why it is doing the less accurate transformation
and how to get it to do the correct transformation instead.<br>
</div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt"
face="Calibri, sans-serif" color="#000000"><b>From:</b>
Qgis-user <a class="moz-txt-link-rfc2396E" href="mailto:qgis-user-bounces@lists.osgeo.org"><qgis-user-bounces@lists.osgeo.org></a> on behalf
of Randal Hale <a class="moz-txt-link-rfc2396E" href="mailto:rjhale@northrivergeographic.com"><rjhale@northrivergeographic.com></a><br>
<b>Sent:</b> 27 February 2020 17:56<br>
<b>To:</b> <a class="moz-txt-link-abbreviated" href="mailto:qgis-user@lists.osgeo.org">qgis-user@lists.osgeo.org</a>
<a class="moz-txt-link-rfc2396E" href="mailto:qgis-user@lists.osgeo.org"><qgis-user@lists.osgeo.org></a><br>
<b>Subject:</b> [Qgis-user] Question On "BallPark Transform"</font>
<div> </div>
</div>
<div>
<p style="border:1px solid black; padding:1.0pt 4.0pt 1.0pt
4.0pt; background:#FFFFCC; font-size:11.0pt;
font-family:"Arial",sans-serif">
<span>CAUTION: This mail comes from outside the University.
Please consider this before opening attachments, clicking
links, or acting on the content.
</span></p>
<div>
<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>
</p>
<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"
moz-do-not-send="true">
https://qgis.org/api/classQgsCoordinateTransform.html#a16adb051fafc25058c0040a310f1606b
</a><br>
</p>
<p>The expanded message in QGIS is: <br>
</p>
<p><span></span></p>
<div class="x_Qynugf">
<p style="margin-top:12px; margin-bottom:12px;
margin-left:0px; margin-right:0px; text-indent:0px">
<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>
<p style="margin-top:12px; margin-bottom:12px;
margin-left:0px; margin-right:0px; text-indent:0px">
<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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If I check the project properties there is no Datum
Transformation defined after all this happens.
<br>
<span></span>
<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>
</p>
<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" moz-do-not-send="true">rjhale@northrivergeographic.com</a>
(p) 423.653.3611
<a class="x_moz-txt-link-freetext" href="http://www.northrivergeographic.com" moz-do-not-send="true">http://www.northrivergeographic.com</a></pre>
</div>
</div>
</blockquote>
<pre class="moz-signature" cols="72">--
-----------
Randal Hale
<a class="moz-txt-link-abbreviated" href="mailto:rjhale@northrivergeographic.com">rjhale@northrivergeographic.com</a>
<a class="moz-txt-link-freetext" href="https://www.northrivergeographic.com">https://www.northrivergeographic.com</a>
(423)653-3611</pre>
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