Kinematic moment-1 (line-of-sight velocity) maps for the shadow-driven spirals, above, and the planet-driven spirals, below, in the J = 2 – 1 transition of the ¹²CO isotopologue; in each case, the moment-1 map of the initial condition is subtracted from that at the end of the simulation. From left to right, we plot disk inclinations of 0^◦, 30^◦, and 60^◦. The FWHM of the fiducial ALMA beam (0.19^′′ × 0.17^′′) is indicated by a gray hatched ellipse. The spiral morphology is much more prominent in the shadow-driven case than in the spiral-driven case.