  We study the collective motion of self-propelled particles affected by the
spatial-dependent noise based on the Vicsek rules. Only the particles inside
the special region will affected by noise. The consideration of the
spatial-dependent noise is closer to reality because of the complexity of the
environment. Interestingly, we find that there exists an optimal amplitude of
noise to adjust the average motional direction of the system. Particular
orientation of the noisy region makes the motional direction of the system
parallel to the orientation of the noisy region. The adjustment of the motional
direction of the system also depends on the shape, the proportion and the
spatial distribution of the noisy region. Our findings may inspire the capture
of the key features of collective motion underlying various phenomena.
