<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head><body dir="auto"><div dir="auto">Hi Springer.</div><div dir="auto"><br></div><div dir="auto">I believe you will need to apply a grid shift file (NTv2). It is available from Natural Resouces Canada and I will send you a link when I get to the office.</div><div dir="auto">The installation is a simple procedure. </div><div dir="auto"><br></div><div dir="auto">Kirk Schmidt</div><div dir="auto"><br></div><div dir="auto"><br></div><div id="composer_signature" dir="auto"><div style="font-size:85%;color:#575757" dir="auto">Sent from my Galaxy</div></div><div dir="auto"><br></div><div><br></div><div align="left" dir="auto" style="font-size:100%;color:#000000"><div>-------- Original message --------</div><div>From: Andreas Neumann <a.neumann@carto.net> </div><div>Date: 2021-04-08 6:52 a.m. (GMT-04:00) </div><div>To: Springfield Harrison <stellargps@gmail.com> </div><div>Cc: qgis-user <qgis-user@lists.osgeo.org> </div><div>Subject: Re: [Qgis-user] WMS Image Projection </div><div><br></div></div>
<p>Hi,</p>
<p>The approx 1.5m offset indicates that QGIS doesn't take a necessary grid-shift file into account. The grid-shift file is a separate file that defines the displacement vectors of coordinate systems with different datums.</p>
<p>As a European GIS user I am not comfortable with North-American CRS, but looking the two CRS up at epsg.io I can see that</p>
<p><a href="http://epsg.io/?q=26910">http://epsg.io/?q=26910</a></p>
<p>vs</p>
<p><a href="http://epsg.io/?q=3157">http://epsg.io/?q=3157</a></p>
<p>EPSG 26910 claims to have an accuracy of 4 m while EPSG 3157 claims to have an accuracy of 1m.</p>
<p>There might be a grid shift file necessary between the two CRS (I am personally unsure if that is the case here).</p>
<p>Since both, the project and the WMS are in the same CRS, I would assume that the offset problems occur with the parcel shapefile.</p>
<p>Do you know a local GIS expert in your region who knows if the transformation between EPSG 26910 and 3157 requires a grid-shift file? I would assume yes, because at epsg.io it indicates that the datums of the two CRS are slightly different: NAD83(CSRS) (<a href="http://epsg.io/4617">http://epsg.io/4617</a>) vs NAD83 (<a href="http://epsg.io/4269">http://epsg.io/4269</a>).</p>
<p>From there - and if we have a proper corresponding grid-shift file - we can help you set up the transformation in QGIS.</p>
<p>Greetings,</p>
<p>Andreas</p>
<p id="reply-intro">On 2021-04-08 10:24, Springfield Harrison wrote:</p>
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<p>Hi Andreas,</p>
<p>Thanks for the reply, I'll try to clarify:</p>
<ol>
<li>Version is 3.16.4</li>
<li>The two municipal sources are being viewed in their own web windows and are displaying the same data<br>
<ol>
<li>They are the source of the property lines for my GIS (downloaded shapefile) and the orthophoto (WMS link, not resident TIFF or other)</li>
</ol>
</li>
<li>The property lines are <span style="font-family: 'Lato,Open Sans,Lucida Grande,Segoe UI,Arial,sans-serif'; color: #000000;">EPSG:3157 - NAD83(CSRS) / UTM zone 10N - Projected, and from the municipal source. I've attached the shapefile if you have the time.<br></span></li>
<li>In QGIS, the ortho is loaded from the WMS source<br>
<ol>
<li><a rel="noopener noreferrer" href="https://mapservices.crd.bc.ca/arcgis/services/OrthoImagery2019/MapServer/WMSserver" style="color: #729fcf; font-family: arial, sans-serif; font-size: 14.399999618530273px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0.4); -webkit-text-stroke-width: 0px;">https://mapservices.crd.bc.ca/arcgis/services/OrthoImagery2019/MapServer/WMSserver</a></li>
<li><span style="color: #000000; font-family: Lato, 'Open Sans', 'Lucida Grande', 'Segoe UI', Arial, sans-serif; font-size: 14.399999618530273px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0.4); -webkit-text-stroke-width: 0px; background-color: #ffffff; display: inline !important; float: none;">EPSG:26910 - NAD83 / UTM zone 10N - Projected</span></li>
</ol>
</li>
<li>The project CRS is EPSG: 26910 but it doesn't seem to change anything by changing that or the source projections (at least within versions of NAD83 UTM Zone 10N)<span style="color: #000000; font-family: Lato, 'Open Sans', 'Lucida Grande', 'Segoe UI', Arial, sans-serif; font-size: 14.399999618530273px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0.4); -webkit-text-stroke-width: 0px; background-color: #ffffff; display: inline !important; float: none;"><br></span></li>
<li>Thus, the same information displays differently online <em>versus</em> in QGIS.<span style="color: #000000; font-family: Lato, 'Open Sans', 'Lucida Grande', 'Segoe UI', Arial, sans-serif; font-size: 14.399999618530273px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0.4); -webkit-text-stroke-width: 0px; background-color: #ffffff; display: inline !important; float: none;"></span>
<ol>
<li>The shift seems to be 1.5 m +/-, quite a lot for what I'm trying to do (building permit with tight setbacks).<br><span style="color: #000000; font-family: Lato, 'Open Sans', 'Lucida Grande', 'Segoe UI', Arial, sans-serif; font-size: 14.399999618530273px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0.4); -webkit-text-stroke-width: 0px; background-color: #ffffff; display: inline !important; float: none;"></span></li>
<li><span style="color: #000000; font-family: Lato, 'Open Sans', 'Lucida Grande', 'Segoe UI', Arial, sans-serif; font-size: 14.399999618530273px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0.4); -webkit-text-stroke-width: 0px; background-color: #ffffff; display: inline !important; float: none;">These are commonly used projections for our neck of the woods</span></li>
<li><span style="color: #000000; font-family: Lato, 'Open Sans', 'Lucida Grande', 'Segoe UI', Arial, sans-serif; font-size: 14.399999618530273px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0.4); -webkit-text-stroke-width: 0px; background-color: #ffffff; display: inline !important; float: none;">The two images I sent earlier depict the differences; in QGIS, earlier orthophotos show a similar or worse displacement. Not so on the municipal web viewer.</span></li>
</ol>
</li>
<li>I've read up on projections in the tutorial and Help file, no revelations there, at least that I could see.</li>
</ol>
<p>Thanks very much for any thoughts you may have.</p>
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Cheers, Spring</pre>
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<div class="v1moz-cite-prefix">On 08/Apr/2021 00:47, Andreas Neumann wrote:</div>
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<p>Hi,</p>
<p>Are there two different CRS involved here? Are the vectors (parcel boundaries) in a different CRS than the orthoimages? This might be a problem of a missing grid-shift file in QGIS.</p>
<p>It is also unclear for me if you load your Orthoimages locally (from tiff-files as well) or from WMS (or both) and only one of them is shifted?</p>
<p>Can you also add information what QGIS version with what proj version you use? You can find this information in the about dialogue in the help menu.</p>
<p>Greetings,</p>
<p>Andreas</p>
<p id="v1reply-intro">On 2021-04-08 02:37, Springfield Harrison wrote:</p>
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<div style="margin: 0; padding: 0; font-family: monospace;" class="v1pre"><span style="white-space: nowrap;">Hello All,</span><br><br><span style="white-space: nowrap;">Re obtaining orthophotos from a WMS server.</span><br><br>Locally we have orthophotos that can be brought into QGIS using the WMS service. They are also viewable on the local government web map service. In both cases I can compare them to the property lines which are from the same source.<br><br>On the government web pages (2), the orthophotos and the lot lines appear to coincide very well. In QGIS, the same two layers are quite misaligned.<br><br>One would suspect a CRS problem but changing the CRS of the Project and the WMS image in QGIS has no effect. Even followed the tutorial to no effect.<br><br>I'm attaching screen shots of the two results. Ant thoughts would be appreciated, thank you . . . .<br><br><span style="white-space: nowrap;">-----</span><br><span style="white-space: nowrap;">Cheers, Springfield Harrison</span><br><br><br></div>
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