Positions of the our PN sample and the known HIPNe retrieved from the literature in the Galactic coordinate system. The filled circles represent HIPNe, with newly detected sources in this observation labeled by their names. The open circles represent PNe where H I is not detected in our observations. The background is an all-sky H I column density map integrated over the full velocity range of −600 km s⁻¹ ≤ v_LSR ≤ 600 km s⁻¹, adopted from HI4PI Collaboration et al. (2016).