PCA: projection of positive data on negative side of plane












1














I did PCA on my data and projected the data on first two eigen vectors. After projection I see that the scatter plot of the data starts from [-1,-1]. My data is all positive. Is it correct for the data to be negative in the projected space.






pca







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    1














    I did PCA on my data and projected the data on first two eigen vectors. After projection I see that the scatter plot of the data starts from [-1,-1]. My data is all positive. Is it correct for the data to be negative in the projected space.






    pca







    share|improve this question

























      1












      1








      1







      I did PCA on my data and projected the data on first two eigen vectors. After projection I see that the scatter plot of the data starts from [-1,-1]. My data is all positive. Is it correct for the data to be negative in the projected space.






      pca







      share|improve this question













      I did PCA on my data and projected the data on first two eigen vectors. After projection I see that the scatter plot of the data starts from [-1,-1]. My data is all positive. Is it correct for the data to be negative in the projected space.






      pca




      pca






      share|improve this question













      share|improve this question











      share|improve this question




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      asked 41 mins ago









      shaifali Gupta

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      136






















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          Yes, it is, there is no reason why a component cannot have negative values.



          Let's take this matrix:



          [[1, 1],[0.5, 1]]


          The eigenvectors have negative values:



          [[ 0.81649658, -0.81649658],
          
    [ 0.57735027,  0.57735027]]





          share|improve this answer





















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            1 Answer
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            active

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            1 Answer
            1






            active

            oldest

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            active

            oldest

            votes






            active

            oldest

            votes









            2














            Yes, it is, there is no reason why a component cannot have negative values.



            Let's take this matrix:



            [[1, 1],[0.5, 1]]


            The eigenvectors have negative values:



            [[ 0.81649658, -0.81649658],
            
    [ 0.57735027,  0.57735027]]





            share|improve this answer


























              2














              Yes, it is, there is no reason why a component cannot have negative values.



              Let's take this matrix:



              [[1, 1],[0.5, 1]]


              The eigenvectors have negative values:



              [[ 0.81649658, -0.81649658],
              
    [ 0.57735027,  0.57735027]]





              share|improve this answer
























                2












                2








                2






                Yes, it is, there is no reason why a component cannot have negative values.



                Let's take this matrix:



                [[1, 1],[0.5, 1]]


                The eigenvectors have negative values:



                [[ 0.81649658, -0.81649658],
                
    [ 0.57735027,  0.57735027]]





                share|improve this answer












                Yes, it is, there is no reason why a component cannot have negative values.



                Let's take this matrix:



                [[1, 1],[0.5, 1]]


                The eigenvectors have negative values:



                [[ 0.81649658, -0.81649658],
                
    [ 0.57735027,  0.57735027]]






                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered 34 mins ago









                Matthieu Brucher

                32311




                32311






























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