To determine which part of Italy has the highest elevation using a map with a compass rose and map key, you would typically look for contour lines or shading that indicates elevation.
Since I don't have the exact map you are referring to, I recommend checking the legend or key for elevation indicators, as well as looking for regions like the Alps in the North, which are known to be the highest mountains in Italy.
Based on general knowledge of Italy's geography, the North would typically have the highest elevation due to the presence of the Alps.
So the response would be: North