• Topology: Encompasses the global shape of the data, and the relations between data points or groups within the global structure
    • Google Pagerank Algorithm
    • Example: Cosmic Crystallography
      • Torus universe (zero curvature)
      • Spherical universe (positive curvature)
      • Other universe (negative curvature)
  • Data: Hyperspectral Imagery
  • Gradient Flow Algorithm
    • identify neighbor with highest density for each data point (arrow points from that point to that particular neighbor)
      • gives a data field
    • follow the arrows to identify clusters

people.rit.edu/wfbsma/data/NINJA_MAIN_self_test_refl_RX.img.html