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I want to use two different data sources which I fetch from a WMS server, but they do not share any CRS. For example, one of my data data sources comes in either EPSG 6706 or EPSG 4258, 25832, 25833, 25834 and Google Maps is not available in neither of these.

Is there any way around it? From everything I can read, it does not seem possible for QGIS (which is the software I'm using) to reproject on the fly data coming from a WMS, but I wish someone here faced this problem and eventually was able to solve it.

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    For me I can set the project coordinate reference system to EPSG:3857 (for Google Maps) then load a WMS that only supports EPSG:4326 using QGIS 3.0.3 on Windows, how are you doing it? – nmtoken Jul 3 '18 at 14:07
  • Actually, I'm doing slightly differently, but tested exactly what you suggest above in a new project and I get the same results. Difference I see is that I'm on MacOS, but that shouldn't change much... 1- Project is set to EPSG:3857 2- Load Google Maps Layer (or OpenStreetMap, I get the same issue) 3- Load WMS which supports only EPSG:6706 4- Italy actually appears in the middle of Red Sea... – Julien Marchand Jul 3 '18 at 14:27
  • So the issue appears to be that either QGIS is doing an incorrect re-projection for EPSG:6706, or the service is not supplying data in EPSG:6706... – nmtoken Jul 3 '18 at 14:39
  • Any way I can quickly find which possibility is actually happening? The URL of the WMS server is located here: agenziaentrate.gov.it/wps/content/nsilib/nsi/schede/… (the PHP URL in the middle of the page, in case your italian is rusty...) – Julien Marchand Jul 3 '18 at 14:57
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    Well, I loaded two separate WMS layers (different servers) into QGIS that support EPSG:4258, both display in the correct location (or to be more exact, my Italian layer from one service lies on top of Italy for my second service), then I added the agenziaentrate service layer (which also says it supports EPSG:4258), and the agenziaentrate layer appears in the Red Sea; so there's no QGIS re-projection going on here... and the error seems to be at the agenziaentrate service end. – nmtoken Jul 3 '18 at 16:16
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I don't have Qgis to hand just now but I think it can reproject WMS layers using on the fly reprojection.

However, if it can't (or for other clients) you can use a local install of geoserver to act as a reprojection proxy by adding the remote server as a new store.

The only downside is that text labels can become hard to read.

  • Yeah, I would have expected on-the-fly reprojection to work too, but it appears to be without any effect. I'm using QGIS 3 (same effect with 3.0 and 3.2), but maybe I'm just doing it wrong, but it appears to be rather straightforward... – Julien Marchand Jul 3 '18 at 11:11
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I eventually got it to work! For some reason, I had to go in the Data Source Manager, in the WMS tab, then change the requested CRS there. When I put it to ETRS89 (EPSG:4258) instead of RDN2008 (EPSG:6706), the data was shown at the right place.

I really don't know where it was failing previously (QGIS not requesting the data properly or the target WMS not answering properly), but I'm glad to have it on track!

  • Sorry for necro-commenting, but were you by any chance using the Italian cadastre WMS? – rrrrrrrrrrrrrrrr Aug 14 at 8:03
  • I was indeed...! – Julien Marchand Aug 15 at 12:29
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    Let me guess, did the data end up overlapping Eritrea instead of Italy? I'm having the exact the same issue! Another user here on StackExchange suggested that some WMS server software returns swapped X, Y coordinates. I'm going to do some further testing in the coming weeks. – rrrrrrrrrrrrrrrr Aug 15 at 16:24
  • Yes, exactly. I commented on your other question. It indeed feels like that, as I made a quick test and interverting X and Y puts Etna right in the middle of Eritrea. – Julien Marchand Aug 16 at 18:08
  • That being said, it doesn't explain why it started to work when I explicitely set the projection to use in the Data Source Manager of QGIS instead of using on-the-fly reprojection like I was initially doing. – Julien Marchand Aug 16 at 18:09

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