These are mainly related to distance and density.

OPTICS Algorithm

OPTICS, or ‘Ordering Points To Identify Clustering Structure’, is a density based clustering algorithm that I developed for segmentation of LiDAR points. It was also my first pull request.

My implementation of the OPTICS algorithm was merged into sklearn for release 0.21, and is available in all current versions. You can find the module documentation here, with more descriptive and narrative documentation here; there’s also demo code.