This is a DEM of a slope. I have made a polygon grid 10X10. I can't find a command to sample the raster by polygons. I've thought something similar with r.neighbours picking the minimum value of the neighbourhood and creating a new DEM were I will use a point grid to sample points. But my question, as I wrote above, is if there is a command to do that directly from polygon sampling. In each of 10X10 box,the algorithm will find the lowest value, and save it, as an extra collumn in the polygon attribute table.