Blog Archives

CORRGRAM: Correlation Matrix (Wavelengths)

April 13, 2012
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CORRGRAM: Correlation Matrix (Wavelengths)

With the "Corrgram" package we can see patterns that can help us to recognize possible inter-correlations in a big matrix. This could be the case to see the correlation to every wavelength respect to all others. This way we can see the high correlation...

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CORRGRAM: Correlation Matrix (Constituents)

April 12, 2012
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CORRGRAM: Correlation Matrix (Constituents)

Thanks a lot to Kevin W., for his comment in my previous post.Corrgram, it a nice package and I found very nice information to understand it a little bit better on Internet apart from the R help page.Corrgrams: Exploratory displays for correlation matr...

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Correlation Matrix (Constituents)

April 9, 2012
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Correlation Matrix (Constituents)

It is important to understand as better as possible our sample set before to develop the regression. Continuing with the “Y” matrix (constituent’s matrix) we have to observe the correlation matrix.In the R Graph Gallery, we can get the code to dr...

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Looking to the difference spectrum

April 9, 2012
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Looking to the difference spectrum

From the previous post, we can make the difference spectrum (once the samples are sorted by moisture) between the sample with the lowest moisture value (position 1), from the sample with the highest moisture value (position 66). This spectra will help ...

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Sorting the "Sample Sets" by constituents

April 8, 2012
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Sorting the "Sample Sets" by constituents

I use to see the videos from:http://www.twotorials.com/and the video:How to order and sort stuff in Ris really useful to apply this concept to organize and understand better our sample sets before to proceed to develop a calibration.The idea of this po...

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VIDEO: "R" Checking the reference values ("Y" Matrix).

March 30, 2012
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VIDEO: "R" Checking the reference values ("Y" Matrix).

(This article was first published on NIR-Quimiometría, and kindly contributed to R-bloggers) To leave a comment for the author, please follow the link and comment on his blog: NIR-Quimiometría. R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web Scraping) statistics...

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Comparing Spectra with different math treatments

March 30, 2012
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Comparing Spectra with different math treatments

It is amazing the quantity of graphics you can develop with R, and how you can show and manage  these graphics. Here in the same plot we compare the raw demo spectra, treated with MSC, SNV and with the first derivative (differences between consecu...

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Dividing the Sample Set in two (Validation & Training)

March 29, 2012
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Dividing the Sample Set in two (Validation & Training)

We have in the Demo sample set “66” samples.  In this post we´ll see one way to divide the set in two parts: one for “Validation” and another for Training or Calibration.The selection will be random. And we are going to use the command:

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SCRIPT for NIR "DEMO" Tutorial – 001

March 28, 2012
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SCRIPT for NIR "DEMO" Tutorial – 001

########### RAW NIR Demo Data##################################demo<-read.table("demo.txt",header=TRUE)VIS<-demoVIS<-as.matrix(VIS)NIR<-demoNIR<-as.matrix(NIR)ALL<-demoALL<-as.matrix(ALL)Protein<-demo...

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VIDEO: Applying "SNV" math-treatment to our raw spectra in "R".

March 26, 2012
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VIDEO: Applying "SNV" math-treatment to our raw spectra in "R".

(This article was first published on NIR-Quimiometría, and kindly contributed to R-bloggers) To leave a comment for the author, please follow the link and comment on his blog: NIR-Quimiometría. R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web Scraping) statistics...

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