I am working on single channel Affymetrix microarrays and using affyPLM I have noticed some spatial artefacts. I have been looking for an appropriate R package to do spatial normalisation but all those I have come across - OLIN, marray, nnNorm - seem to be designed for two-channel arrays. Does anyone know of one designed for single channel arrays? Or perhaps though they say they are for two-channel arrays they also accomodate single-channel arrays? Many thanks in advance, Scott -- output of sessionInfo(): R version 3.0.0 (2013-04-03) Platform: x86_64-w64-mingw32/x64 (64-bit) locale: [1] LC_COLLATE=English_United Kingdom.1252 [2] LC_CTYPE=English_United Kingdom.1252 [3] LC_MONETARY=English_United Kingdom.1252 [4] LC_NUMERIC=C [5] LC_TIME=English_United Kingdom.1252 attached base packages: [1] stats graphics grDevices utils datasets methods base -- Sent via the guest posting facility at bioconductor.org.