Theory, Examples & Exercises
- Constrained ordination
Non-metric alternative to PCoA analysis - it can use any distance measure among samples, and the main focus is on projecting the relative position of sample points into low dimensional ordination space (two or three axes). The method is distance based, not eigenvalue based - it means that it does not attempt to maximize the variance preserved by particular ordination axes and resulting projection could therefore be rotated in any direction.
The algorithm goes like this (simplified):