Problem with operations on large files ("cannotallocate vector of size xx")
Hi, Blockwise calculation does not make sense with PCA as you will end-up with different components in each block. As I wrote earlier, to calculate the PCA based on all pixels you should calculate the covariance matrix first, which can be done in a memory safe way (raster::layerStats) and then feed that into princomp. see: https://github.com/bleutner/RStoolbox/blob/master/R/rasterPCA.R cheers, Benjamin
On 03.02.2017 15:10, Maurizio Marchi wrote:
Yes, Tina is right, anyway consider also that, looking at my code, the prcomp function and the predict functions can be run with different objects. For instance the pca can be run on a 5 km raster map (aggregated) or on the random samples (you will see that with an adequate number of points the results will be the same) but the predict function can be launched on the original dataset (1km) obtaining the pca components with the desired spatial resolution Regards, maurizio ?-- Maurizio Marchi, PhD - Forest Science, Ecological Modelling Council for Agricultural Research and Economics (CREA, Italy) SkypeID: maurizioxyz https://scholar.google.it/citations?user=_2X6fu8AAAAJ&hl=en #-----# http://ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=search.dspPage&n_proj_id=5035 www.selpibio.eu ??www.eufgis.org? [[alternative HTML version deleted]]
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