I am trying to use QGIS3.10 to analyze the area of forest within regions. It looks like this enter image description here

where the polygons belongs to WFS layer and Rasters belongs to WMS layer. The legends fo Raster suggests that the raster contains different catagories, looks like this enter image description here

I would like to find the percentage of green areas in polygons based on percentage coverage info provided in Raster. I have tried converting raster to polygons (with no polygons outcome), raster zonal analysis (with error message) and Extract layer content (no desired outcome).

Can anyone suggest me a way to extract the data from it?

I have knowledge in Python, but I have no idea on how to handle this kind of data.

Dataset used in this case:

http://geo.stat.fi/geoserver/postialue/wfs -> Paavo-postinumeroalueet 2019 https://image.discomap.eea.europa.eu/arcgis/services/GioLandPublic/HRL_TreeCoverDensity_2015/MapServer/WMSServer -> Tree Cover Density 2015

  • I think that you need an own copy of the data. About the WFS layer, exporting it as a vector layer should work. About to extract the data of the WMS layer, it can be done with a GetMap request mehod. I wrote an answer to get a WMS raster dataset with GRASS GIS to the following question: gis.stackexchange.com/questions/305663/… Commented Nov 17, 2019 at 17:05


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