[BioC] One-Color Aglent Data into Limma GUI

Martin Morgan mtmorgan at fhcrc.org
Tue Oct 9 15:34:07 CEST 2007


Hi Elliot,

"elliot harrison" <e.harrison at epistem.co.uk> writes:

> Hi All,
>  
> I'm trying to work with One-color agilent data without much luck.
> http://article.gmane.org/gmane.science.biology.informatics.conductor/128
> 18/match=agilent 
>
> I've tried the above method but as I posted before I get stuck on the
> following error.
>  
> Error in readGenericHeader(fullname, columns = columns, sep = sep) : 
> Specified column headings not found in file

Sorry your earlier post didn't get a reply. Try narrowing things down
to their essence, and post something as close to reproducible as
possible. I bet you end up with the problem here

targets <- ...
G <- read.maimages(targets,
                   columns = list(G = "gMeanSignal", Gb = "gBGUsed",
                     R = "gProcessedSignal", Rb = "gBGMedianSignal"))

The likely candidates are either that one of the 'targets' is
incorrect, or that one of the files pointed to by targets does not, or
appears not, to contain one of the columns. So the next challenge is
to figure out which file is problematic. I'd try 

> options(error=recover)

and then execute read.maimages. You'll then want to choose one of the
listed 'frames' (probably labeled something like
readGenericHeader). You'll be in something called the browser (see
?browser) and will be able to evaluate any R expression. In
particular, when you've navigated to the right frame (this might take
a bit of experimentation), you'll be able to print out 'fullname', the
name of the file you're having trouble with.

Your agilent files are likely text files, and you can likely look
inside them for strings matching the column names you've listed. If
the column names aren't found, then you've discovered why you're
getting the error! If they are found, then report back with a
thoughtful and concise digest of your discoveries. You do want to be
careful not to 'save' files you're looking at, unless you know your
text editor won't try to be 'helpful' in some way, e.g., by saving the
file in a different encoding.

Please also include the output of sessionInfo().

Martin

> As such I thought I'd try a different approach and have a go with the
> LimmaGUI.
> I've faked green channel columns in my files like this which I hope to
> ignore once imported.
>
> FEATURES	FeatureNum	Block	Row	Col	SubTypeMask
> SubTypeName	ProbeUID	ControlType	ProbeName	GeneName
> 	SystematicName	PositionX	PositionY	gProcessedSignal
> rProcessedSignal	gMeanSignal	rMeanSignal
> 	gMedianSignal	rMedianSignal	gBGUsed	rBGUsed
> DATA	1	1	1	1	0		0	1
> GE_BrightCorner	GE_BrightCorner	GE_BrightCorner	9790.72	223.949	358.8079
> 1.52E+04	1.10E+04	1.10E+04	10446	10446	78.8743
> 78.8743
>
> When I try to import the files I gives an error saying it was unable to
> read the image processing files
>
> I've also added a Block column as the next error is in getLayout(gal)
> GAL file must contain Block, Column, Row error.
> Then Error in Matrix and other but I guess this is all due to the file
> not being read properly in the first place.
>
> I am using another analysis package as well so I am analysing my data
> but there is so much more to R. 
> Any help getting going would be greatly appreciated.
>
>
> Many Thanks
>
> Elliott
>
>
> This message has been scanned for viruses by BlackSpider...{{dropped:3}}
>
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-- 
Martin Morgan
Computational Biology Shared Resource Director
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N.
PO Box 19024 Seattle, WA 98109

Location: Arnold Building M2 B169
Phone: (208) 667-2793



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