Clipping raster by polygon

Question

I tried to clip a raster from processing toolbox, using Clip Raster by Polygons extent but I get the error message below.

This map/raster was connected to an URL by using WMS/WMTS. Then the map was transfered to the Layers Panel by double clicking. Does the map lying in Layers folder now require some additional conversion maybe and how?

ERROR 4: `crs=EPSG:25832&dpiMode=7&format=image/png&layers=topo4&styles=default&tileMatrixSet=EPSG:25832&url=https://opencache.statkart.no/gatekeeper/gk/gk.open_wmts?Version%3D1.0.0%26service%3Dwmts%26request%3Dgetcapabilities' does not exist in the file system, and is not recognized as a supported dataset name.
Process returned error code 1
Execution completed in 0.16 seconds

Answer 1

As mentioned already by @Erik, you first have to save the raster to a local file. Right click on the layer in the layer panel / Export / Save as..., define path/filename, set desired extent and resolution of the raster, see screenshot.

If you afterwards want to clip the raster with a polygon, set this polygon layer's extent as the extent for the raster export.

A horizontal/vertical resolution of 200 (as in the screenshot) means that each pixel has a size of 200 map units (cartesian measurement in layer units, here: meters). For the selected extent, this means a raster size of 5106 x 3206 pixels. You could also set the numbers of colums/rows (no. of pixels horizontally and vertically) you want for the output, but then you risk that the pixels will not be squares any more, but rectangles (different horizontal/vertical size).