I am calculating PCA using a numpy/python approach. The principal components are in the form of GIS grids (rasters), created in a manner very similar to the GRASS GIS approach described here: http://grass.fbk.eu/gdp/html_grass62/r.covar.html
Every cell in an output component grid contains a PC score. Within each component grid there is a range of negative to positive PC scores. Is it okay to convert the scores to absolute value? Is the direction of the value important, or just the relative within-component (i.e., within-grid) magnitude?