Questions tagged [biplot]

Biplot or dual plot is an exploratory graph to present - as points or vectors - both the observations (sample) and the variables of the data. The axes are typically latent principal dimensions. Biplot is often used to depict principal component analysis, correspondence analysis, and other multivariate methods.

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Biplot interpretation

I'm quite confused as to interpreting results from a biplot. I am trying to find out which variable is negatively correlated with the variable Hue and which variable is uncorrelated with Hue. At this ...
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Biplots in R vs in SAS, does the scale parameter differ?

When reading up on biplots in a principal component context, I found that in SAS setting c = 0 gives you a GH biplot that represents the vectors correctly.[1] The same applies in STATA.[2] From what I ...
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Replicating regression biplot calculations

I am working through Chapter 2 of Biplots in Practice (available here: https://www.fbbva.es/wp-content/uploads/2017/05/dat/greenacre_c02_2010.pdf) Some of the code is provided in the appendix: https://...
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How to interpret a PCA Biplot? [duplicate]

I constructed a PCA plot from a very high-dimensional dataset that contains features relating to fraud. After creating the PCA plot, I created a biplot with the features to see how they interact. The ...
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biplot of PCA data gives very unusual

Very much a new at data analytics, with some functional understanding of statistics. I was referred to this site from elsewhere. I am looking at ca. 1000 optical spectra, data available from the ...
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PCR biplot -shape [duplicate]

Working on 4600 x 1000 matrix (spectra), looking to do a PCA study. I got the attached biplot output. I have no idea how to interpret. The code is good, I have looked at model examples and can ...
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Interpretating bibplot on covariance Matrix

Would be the biblot interpretation on convariance matrix and correlation matrix the same? For example biplot below was generated by PCA with covariance matrix on. Should i still interpretate any ...
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Visualizing shared instances of p-values<alpha across large numbers of treatments

Assume a data table that presents the p-values of a large number of independent runs of a statistical hypothesis test. Each run represents a single test with two possible hypotheses (i.e., null and ...
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Can correlations between all variables be extracted from PCA/RDA biplots?

I am performing a systematic review of the literature for my dissertation, and I need to extract the relationship between two variables from the results of multivariate analyses, particularly ...
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Is it possible to code in a CA the additional variables in dummies variables

I'm doing a correspondence analysis as part of a study. Unfortunately, one of the commands I use with R doesn't work because I have supplementary categorical variables that the package doesn't ...
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Interpreting the loads in a biplot

I came across a doubt about the interpretation of the biplot. I know that there are lot of questions related to this topic but I have a very concrete question, but I don't find any response. Suppose ...
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PCA biplot vs separate score+loading plots

In the context of PCA, is there any reason why the scores and loadings are put into a single plot, the biplot? Do they interact somehow or it is just a preference of just 1 plot over 2 plots?
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How to analyze this biplot of PCA?

I have dones a PCA analysis about measurement of a fish morphometric between female and male. After the PCA result came out with biplot graph, I was a little bit confused to interpret this data. It ...
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PCA and visualization using biplots on data with mixed types

I have a dataset of dimensions 1500x200 where the predictors are both quantitative (discrete and continuous), as well as qualitative (categorical and ordinal) and the dependent variable is continuous. ...
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How variables (constrained loadings) are selected in a biplot CCA

I am trying to do a Canonical correspondence analysis (CCA) using the community data and chemical data. I have my family level taxonomic data as community data. In chemical data I have 18 variables: ...
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Biplot computation in SVD

I'm trying to implement PCA biplot. I've got much of the concepts nailed down specially thanks to: Relationship between SVD and PCA. How to use SVD to perform PCA? and Positioning the arrows on a ...
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Arrows of underlying variables in PCA biplot in R

At the risk of making the question software-specific, and with the excuse of its ubiquity and idiosyncrasies, I want to ask about the function biplot() in R, and, ...
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When plotting PCA analysis with loadings on top, loading arrows come out way too short [duplicate]

I am trying to make a reasonable looking PCA analysis, where not only data are projected in two axis, but also the loadings of the data are projected on top of the data. Similar to the following ...
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R multiple correspondence analysis loadings

I'm running a multiple correspondence analysis in R using the FactoMineR package: ...
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Linear Discriminant Analysis biplot [closed]

I am not sure about plotting a biplot for LDA. Suppose I have a 3 feature data set with 3 classes. Then, I perform LDA to reduce the dimensionality to 2. How can I create a biplot for the LDA? My ...
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Joint Dimension Reduction and Clustering in R

I am trying to understand the Joint Dimension Reduction and Clustering in R which comes in its new package clustrd where they have followed (this Article). The <...
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When doing PCA, is it possible or correct to find the correlation between variables and the first two components combined?

So I saw a correlation matrix between variables and components like below: ...
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I want to run a same result of biplot in R

There is a software called Brandmap$^1$ which can return a biplot from a matrix. I am trying to run the same result in R but the coordinates are not the same. First I input a simple matrix into the ...
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How to interpret ggbiplot() visualization of PCA in R? [duplicate]

To apply and visualize PCA in R often ggbiplot() is used. What is the meaning of this plot ? Why it is useful for PCA ? We can consider this example: https://tgmstat.wordpress.com/2013/11/28/...
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Angles between variables on a PCA biplot and correlations between the variables

A friend or mine has performed a PCA and he asked me for help about interpretating a biplot. In that biplot I found that the vector representing a variable, say A, forms a very wide angle, perhaps ...
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Interpreting overlapping arrows on a PCA biplot: does it mean that the variables are redundant?

I'm new in principal component analysis (PCA) and I don't really understand the biplot representation of its results, so I would really appreciate some guidance. Having the example of the illustration ...
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When to use distance biplot vs. correlation biplot in PCA

I wonder what could be good examples of using scaling 1 and 2 for a principal component analysis biplot. By examples, I mean ecological examples or applied examples of the PCA scaling so that one can ...
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Data space, variable space, observation space, model space (e.g. in linear regression)

Suppose we have the data matrix $\mathbf{X}$, which is $n$-by-$p$, and the label vector $Y$, which is $n$-by-one. Here, each row of the matrix is an observation, and each column corresponds to a ...
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Varying lengths of eigenvectors on a PCA biplot [duplicate]

I'm conducting a PCA in Matlab on standardized variables. My goal is to interpret angles = loadings, correlations bw. variables and PC-axis directions = vectors point to the direction of the ...
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Confused about scores and loadings in this PCA biplot

I was investigating the interpretation of a biplot and meaning of loadings/scores in PCA in this question: What are the principal components scores? According to the author of the first answer the ...
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Interpretation of biplot in PCA

Blue points all appear in the lower right-hand quadrant in the plane formed by the first two principal components. Is it a good interpretation of the biplot (right panel) to say that blue points are ...
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Does biplot() function in R use rotations or loadings to plot arrows? [duplicate]

For following code performing principal component analysis: ...
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PCA - more than 2 principal components for >80% variance

I have analyzed some datasets using prcomp and some of my data is nice and amenable to PCA. But the summary of one set is showing that at least 6 components are needed to cover 80% of the variance. I'...
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43 votes
1 answer
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PCA and Correspondence analysis in their relation to Biplot

Biplot is often used to display results of principal component analysis (and of related techniques). It is a dual or overlay scatterplot showing component loadings and component scores simultaneously. ...
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Positioning the arrows on a PCA biplot

I am looking to implement a biplot for principal component analysis (PCA) in JavaScript. My question is, how do I determine the coordinates of the arrows from the $U,V,D$ output of the singular vector ...
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How to interpret this PCA biplot?

I am approaching PCA analysis for the first time, and have difficulties on interpreting the results. This is my biplot (produced by Matlab's functions pca and ...
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21 votes
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What is the proper association measure of a variable with a PCA component (on a biplot / loading plot)?

I am using FactoMineR to reduce my data set of measurements to the latent variables. The variable map above is clear for me to interpret, but I am confused when ...
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12 votes
1 answer
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What is the difference between "loadings" and "correlation loadings" in PCA and PLS?

One common thing to do when doing Principal Component Analysis (PCA) is to plot two loadings against each other to investigate the relationships between the variables. In the paper accompanying the ...
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Understanding biplot for compositional data

Say in the biplot of some compositional data, I discovered that the links $\vec{AB}$ and $\vec{CD}$ intersect at roughly 90 degrees. So I can say that $\log {A\over B}$ and $\log{C\over D}$ are ...
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Interpreting a PCA Biplot of a time series?

I had a question in regards to PCA with times series data, and specifically how to possibly interpret it. Normally, PCA is used by other software that I use in relation to de-noising a data set by ...
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PCA figure formatting options in R

I've completed PCA analysis, in R with VEGAN package, of some ecological data on tree health. There are 80 trees total (so, 80 'sites') divided into four treatment categories. I've got the data ...
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Interpreting negative coordinates and origin in 2D correspondence analysis plot [duplicate]

Why are there negative values in the range of the plot? How is the center of the plot (i.e., the $0.0$ point) found? How did the black-brown points end up in the third quadrant of the plot? Why ...
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11 votes
3 answers
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Can the scaling values in a linear discriminant analysis (LDA) be used to plot explanatory variables on the linear discriminants?

Using a biplot of values obtained through principal component analysis, it is possible to explore the explanatory variables that make up each principle component. Is this also possible with Linear ...
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4 votes
1 answer
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What are the units in this PCA biplot? [duplicate]

This is a plot of my data These are the values: ...
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3 votes
1 answer
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Interpretation of PCA biplot?

I just ran my first ever PCA, so please excuse any naivety on my part. As input, I used five years worth of the following: S&P/ASX 200 A-REIT S&P/ASX 200 Consumer Discretionary S&P/ASX ...
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22 votes
2 answers
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What are the four axes on PCA biplot?

When you construct a biplot for a PCA analysis, you have principal component PC1 scores on the x-axis and PC2 scores on the y-axis. But what are the other two axes to the right and the top of the ...
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Difference beween supplementary and active variables in PCA - Interpretation on obsevations?

I would like to introduce two supplementary variables into a PCA I'm conducting on a set of data measuring concentration in different material phases. However I'm unclear as to how to interpret the ...
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How to interpret this PCA biplot coming from a survey of what areas people are interested in?

Background: I asked hundreds of participants in my survey how much they are interested in selected areas (by five point Likert scales with 1 indicating "not interested" and 5 indicating "interested"). ...
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Is a Biplot suitable ? Domestic Violence VS Non-Violence data

I have a small data set that consists solely of counts. I have several variables. For example State, for each state (Mexican States), for example, Tamauplipas I have the counts of domestic violence ...
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What do the arrows in a PCA biplot mean?

Consider the following PCA biplot: ...
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