Fig. 2
From: Remote sensing of burned areas via PCA, Part 1; centering, scaling and EVD vs SVD
Conventional mean-centered EVD-based PCA on the correlation matrix, thus scaled, of a bi-variate data set composed by a post- and a pre-fire MODIS surface reflectance band 2. Black dots and grey asterisks are respectively samples of burned surfaces and vegetation. The original coordinate system (light greyed) has been shifted after centering. The shape of the point-scatter has altered after scaling and rotated after PCA to the direction in which the spread of the data onto the new axes (dashed axes, PC1 and PC2) is maximised. These are restricted to be orthogonal