I've been trying to get a slope raster from a DEM, so I can reclassify it and aggregate it with land use data.
The problem is that my slope raster seems to have a lot of distortion (diagonal lines). I've tried changing some settings but I really have no idea what can be causing this. I'm using a projected CRS, EPSG 31983. I've got the DEM from whole state where I live in Brazil, then I had to clip it to my AOI, and that is all the processing I made with the DEM before trying to get the slope.
Some information about the DEM file from the metadata:
Driver: GDAL provider
Band 1 SourceBandIndex=0
Dimensions - X: 692 Y: 346 Bands: 1
Pixel Size: 28.8724,-28.8724
No Data Value: 0
Data Type: Float32 - Thirty two bit floating point
Layer Spatial Reference System: +proj=utm +zone=23 +south +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
Layer Extent (layer original source projection) - 227546.4710596329532564,7402400.2644091211259365 : 247526.1508292471116874,7412390.1042939284816384
Band No: 1
Min Val: 531.9765014648
Max Val: 960.2605590820
Sum of squares: 1395234469.1412367821
Standard Deviation: 76.3367047628
Sum of all cells: 145634332.9768066406
Cell Count: 239432
Slope generated from DEM (a lot of odd diagonal lines):
I went to the source again, and got the raw DEM to process/clip it again. This time around everything seemed to work just fine. I believe what happened was some kind of mismanage when warping the raster.
I didn't get the chance to try Freighty's solution because SAGA and Orfeo are not working properly for me, but I believe if you have access to them, it's a feasible solution.