[BioC] limma layout query (genepix GAL file)
smyth at wehi.edu.au
Sat Oct 1 12:52:07 CEST 2005
At 08:00 PM 1/10/2005, bioconductor-request at stat.math.ethz.ch wrote:
>Date: Fri, 30 Sep 2005 11:50:58 +0200
>From: Dave Berger <dberger at postino.up.ac.za>
>Subject: [BioC] limma layout query (genepix GAL file)
>To: bioconductor at stat.math.ethz.ch
>Message-ID: <433D0A82.B293F5F at postino.up.ac.za>
>Content-Type: text/plain; charset=us-ascii
>using R version 2.1.1
>limma version 1.9.6
>We know our Slide layout is
>however when we read in layout from GAL file as below
>can you explain why this does not correspond to our expected layout?
>below is an extract of first 2 blocks from our GAL file
>"M64_AtSSH_correct.gal" from Genepix version 5.1
>The remaining 22 block follow the same row and column patterns.
1. There actually is no foolproof way to determine the printer layout
information from the columns of a gal file, because GenePix stores only the
block numbers. Hence getLayout() is forced to assume ngrid.c=4, which is by
far the most common value. This is actually the reason why the printer
layout information is not set automatically by read.maimages() for GenePix
data. There is no way to be sure it is right without manual intervention.
2. You could try using getLayou2() instead, which is an experimental
function designed to get around the above problem. If that doesn't work,
set the printer layout information manually.
3. There is actually no need to use readGAL() at all with GenePix data. You
will see that read.maimages() already populates RG$genes with the relevant
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