Computation of the distance metric (d) using polar coordinates r and θ, as discussed in Appendix C, for S CrA (top panels) and HL Tau (bottom panels). Left panels: Radial distance for each point on a streamer from the origin point (0,0). The origin point is also assumed to be the position of the center of mass for the protostellar system. Middle panels: Polar angle (θ = arctan (ΔDec/ΔRA)) for each point on a streamer with respect to the mean direction of the streamer points in the bin closest to the origin. Right panels: Distance metric for each point on a streamer computed using the polar coordinates (r and θ) and the weighting factor (w, = 1 by default).