Spatial distribution of the clean samples in the Galactocentric cylindrical coordinate system (R, z). ﹩{{ \mathcal S }}_{c}﹩ (blue dots) and ﹩{{ \mathcal S }}_{d}﹩ (magenta dots). The two distributions overlap strongly, with ﹩{{ \mathcal S }}_{c}﹩ extending farther in both the radial and vertical directions, demonstrating the advantage of the photometric method in probing depth.