QGIS 2.18.24 – which I use for work and cannot update – seems to struggle with some WMS and WMTS layers. They seem to render at an incorrect resolution, although they appear aligned properly.
This is Mapbox (WMS):
And this is esri World Topo (WMTS):
As you can see (click to enlarge), both look really crappy. Seems like the resolution is way off. Other layers do not have such issues. Am I missing something obvious here?
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What is wrong with using the official DTK by the LGB (geobasis-bb.de/geodaten/geo_wms_uebersicht.htm)?– ErikNov 20, 2019 at 12:32
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3Is your QGIS project using some other CRS than the native one for the WMTS Service?– user30184Nov 20, 2019 at 12:35
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@user30184, yes, I use EPSG:3059.– kolmsNov 21, 2019 at 7:16
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1The texts like "Berlin" in the screenshots are slightly rotated and I suppose that in some part of the chain the tiles are re-projected. Check again from QGIS if the services really support tilesets in EPSG:3059. And have a try by changing the CRS of QGIS into EPSG:3857 and see if it makes difference. Naturally you must then select a tileset that is in EPSG:3857 as well.– user30184Nov 21, 2019 at 7:47
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1 Answer
I'd strongly suggest that you ask your IT team to consider allowing you to have at the least a parallel install of QGIS 3.4LTR or QGIS 3.10, as they've made inumerable significant improvements in every area since 2.x, not least of which was a change to the raster rendering pipeline that allows for pixel-perfect rendering at native resolution, which did not occur in prior releases, as the raster data were still being scaled (resulting in the distortions you see in your imagery).
For your specific case, you might be best off to convince your IT team to wait for QGIS 3.10LTR, which should be out soon (2020-02-21), as this change has been committed to QGIS Master, 3.8, 3.10, and 3.10LTR, with no evidence of being backported to any other release.
Changelog for QGIS 3.8:
Feature: Improved “Zoom to Native Resolution” behavior
We’ve improved the “Zoom to Native” action, so it now works correctly with tiled (e.g. WMTS/XYZ/ArcGIS MapServer) layers, by zooming to the closest native tile resolution. Additionally, we tweaked tile rendering so that pixel-perfect rendering occurs when the map is viewed at a native tile resolution. The result: super-crisp map renders when using tiled layer sources!
Summary QGIS 3.8 and newer have the improved raster rendering logic which will allow for pixel-perfect rendering, even of webmap layers.
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1Thank you for the response. I do have QGIS 3.10 installed on my own computer, and I experience the same issue there as well. Let's hope the changes in upcoming releases fix that.– kolmsNov 21, 2019 at 7:15
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1I see that in a comment above you mention you use a CRS that isn't EPSG 3857/4326. QGIS is going to have to reproject (distort) the tilesets because they're not in their native/served CRS, which is going to introduce some artifacting. As suggested by user30184, you should re-load the tilesets in a native EPSG:3857 project and see if they behave better (they should). If not, time to file a bug at the QGIS GitHub! Nov 21, 2019 at 14:15