Left: NGC 628 R-band PA as a function of inner radius for deprojected image. A stable mean PA is determined for the m = 2 harmonic mode (black solid line) from a minimum inner radius of 30 pixels (12′′) to a maximum inner radius of 200 pixels (80′′), with an outer radius of 440 pixels (176′′). The pitch angle can be seen to decrease dramatically with increasing radius beyond approximately 50% of the outermost radius and becoming chaotic near the edge; this is due to a shrinking annulus of measurement reducing the viability of pitch angle measurement in the outer regions of the galaxy. Right: an overlay image of a 14.98 deg pitch angle spiral on top of NGC 628.