The flowchart of the HDBSCAN clustering applied to solar magnetograms on 2023 February 1. (a) The result after threshold segmentation. (b) Minimum spanning tree construction with random 5000 pixels from (a). (c) Single linkage hierarchy. (d) Condensed hierarchy tree. (e) The HDBSCAN clustering result. (f) The clusters with a bounding box and the background.