I want to create a .png print with a world projection file from a specific WMS. The WMS in question is Polish national Geoportal service containing hypsometric data. Here's the WMS adress: http://mapy.geoportal.gov.pl/wss/service/wmsimg/guest/ISOK_HipsoDyn/ImageServer/WMSServer The projects and WMS coordinate systems are the same. I have no idea why the output is "tiled" and has different colours for each tile.

enter image description here

Here's the output as visible in the Print Composer. However, the results when printing into the .png file are as follows:

enter image description here

However, when I switched the output quality to 50 DPI ("tiled" one is at 150 DPI") the result was almost correct. enter image description here

I've searched through similar questions here, but none of zoom/scaling issues people usually encounter have to do with "tiled" outputs, just with quality. And quality at 150 DPI is correct, same for 300 DPI; it's "just" the "tiling" and different colouring that is a problem.

If anybody ever encountered the same problem, I'll be glad for any help ;]

  • Have you tried using a larger page size with the lower DPI? Sometimes you can trick the WMS to give you the desired tile level this way. – csk Feb 17 '18 at 17:21

I'm not an expert on layer types but couldn't this data source be a WMTS layer (Web Map Tile Service)? I guess this is probably a logical way to represent the elevation data you're requesting for every zoom level since the entire dataset would be too large to supply at each request. The different colouring might also be explained by the tiles and the zoom as well; since the data is requested per individual tile it also adjusts the colour scale according to the data range that is available in that tile. This is obviously different for a zoomed in portion of the map as opposed to Poland entirely.

If anyone could clarify if I'm on the right track here and elaborate in a more scientific manner, be my guest.

  • 1
    This data source is available in both WMTS and WMS formats! This explains the tiles and colourings. I've used the WMTS service instead of the WMS, but it unsurprisingly resulted in the same tiled output. Is it possible to create a WMTS query to download and save specific tiles with unified colouring? QGIS is somehow able to represent a specific area in this unified colouring, as I've shown in the print composer preview and the 50 DPI print composer output... – Chimney343 Feb 16 '18 at 12:51

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