1. Application of Decision Trees Decision trees have been used in many areas. One notable area is star-galaxy classification. As an example, the Space Telescope Science Institute In Baltimore MD, has built a Guide-Star Catalog. One billion objects – digitized photographic data. Images have high variation in brightness.

2. Application of Decision Trees Sky Survey II plate. Squares are stars; Circles are Galaxies. Classification is hard for faint objects).

3. Application of Decision Trees Example of Catalog Processing (“From Digitized Images to Online Catalogs” by U. M. Fayyad, S. G. Djorgovski, N. Weir. AI Magazine 1996)