Results from modified SPA+ method plotted on top of synchrotron-intensity map for the Cygnus Loop’s northern region. Each analysis spot corresponds to the classification obtained from a 2.5 pc × 2.5 pc sub-region. The rings show the identification of the dominant mode from the classification parameter, A₄/A₂. The red dots show the detection of fast modes through the asymmetry parameter, B₄/A₂. The green and red colours show the mode dominance of Alfvén and compressible modes, respectively. The regions where the SPA+ mode classification leads to mode ambiguity have been removed from the analysis.