.. _book_fig_chapter7_fig_PCA_LLE: PCA Projection of SDSS Spectra ------------------------------ Figure 7.9 A comparison of the classification of quiescent galaxies and sources with strong line emission using LLE and PCA. The top panel shows the segregation of galaxy types as a function of the first three PCA components. The lower panel shows the segregation using the first three LLE dimensions. The preservation of locality in LLE enables nonlinear features within a spectrum (e.g., variation in the width of an emission line) to be captured with fewer components. This results in better segregation of spectral types with fewer dimensions. .. rst-class:: horizontal .. image:: ../images/chapter7/fig_PCA_LLE_1.png :align: center :scale: 100 .. image:: ../images/chapter7/fig_PCA_LLE_2.png :align: center :scale: 100 .. raw:: html