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Hello dear QGIS Community, I am setting up QGis on my MacBook M1 with Big Sur and facinging various issues with layers and external sources. After having worked for a while with QGIS on Windows 10 and having recently switched to an M1 Mac Book Pro not supporting Bootcamp, I started to use QGis directly in macOS (11.1) and via Rosetta.

Unfortunately, the setup seems to be complicated. The resolution of connected WMS/WMTS Layers is unusable. Most of them disappear after zooming in at more than 1:12000 or so.

Sceenshot of the low resolution

It concerns public sources like Openstreetmap or Openrailwaysmap as much as non-public sources.

I tried it on different display and various versions of QGIS. It happens on every display, whether external or internal and on 3.10 as much as 3.16. example of blurriness I'd be happy if someone can assist me put on me on the right direction to fix this issue - or to find out whether this is a bug at the moment due to M1 Silicon platforms.

Felyxorez
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  • This has nothing to do with Mac, it seems to be an inherent issue of the services that they are quite pixelated at certain scales, most likely due to fewer available scales of the tiles. E.g. tracks at Berlin Mainstation look quite pixelated at 1:3500 and 1:1750, while below 1:1000 the tracks are easily readable. – Erik Jan 27 '21 at 15:42
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    This issue was that because of swiss habit, I set the projection to traditional swiss CH1903 / LV95 instead of comon WGS 84, thus deforming the tiles in a way they couldn't be rendered properly. – Felyxorez Feb 02 '21 at 06:59
  • Tiles are usually rendered in EPSG:3857, not WGS 84 (EPSG:4326) so for best visual results, using that CRS and the exact zoomlevels at which they are rendered is the best approach. – bugmenot123 Jan 31 '22 at 12:27

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If you need to stay in your local Swiss projection (EPSG:2056), you could use GDAL-VRT to enhance the quality of the OSM WMTS layer.

Therefore you have to download the OpenStreetMap XML description file (https://raw.githubusercontent.com/OSGeo/gdal/master/frmts/wms/frmt_wms_openstreetmap_tms.xml) and transform it to EPSG:2056 using GDAL Warp with a dedicated resampling method (i.e. -r Lanczos). Then drag the VRT file into your map canvas.

gdalwarp -r lanczos -of VRT -t_srs EPSG:2056 frmt_wms_openstreetmap.xml osm.vrt

You can test different resampling algorithms (i.e. bilinear,cubic,...) to get best results. Simply change the line <ResampleAlg>Lanczos</ResampleAlg> in osm.vrt.

If you like to freeze the OSM WMTS to a certain tile level, you can change the XML description file (i.e. <TileLevel>17</TileLevel> for the sample image)

enter image description here

christoph
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