[R] creating a color display matrix
Jim Lemon
jim at bitwrit.com.au
Fri Jul 28 00:56:40 CEST 2006
Kartik Pappu wrote:
> Hello all,
>
> I am trying to use R to create a colored data matrix. I have my data
> which (after certain steps of normalization and log transformation)
> gives me a "x by y" matrix of numbers between 0 and -5. I want to be
> able to create from this matrix of numbers a "x by y" image (box) that
> contains x*y squares and somehow uses the value in the original matrix
> to come up with a color that corresponds to the number. Hence each box
> will be colored on a scale between 0 and 5. For example my data could
> look like this:
>
> X1.FcH X2.FcH X3.FcH X4.FcH X5.FcH
> X6.FcH X7.FcH
> 1-AP 0.09667593 -4.66298640 -1.28299697 -4.8739017 -4.95862831
> -5.178603 -4.878524750
> 2-AP -4.69186869 -0.08547776 -4.56495440 -4.8348255 -4.80256152
> -5.121531 -4.894347108
> 3-AP -1.71380667 -4.52626124 -0.06810053 -4.8703810 -4.65657593
> -5.024595 -4.824712621
> 4-AP -4.47968850 -4.48604718 -4.44314403 -0.1569536 -4.86436977
> -4.988196 -4.550416356
> 5-AP -4.64616469 -4.53888807 -4.78163386 -4.9162949 -0.01729274
> -5.061663 -0.769960777
> 6-AP -4.61047573 -4.60917414 -4.72514817 -5.0084772 -4.87797740
> -0.284934 -1.782745357
> 7-AP -4.48157167 -4.61850313 -4.72241281 -4.8694868 -1.66122821
> -3.887898 -0.002522157
>
> How do I make a 7 x 7 box that has 49 squares and each square has a
> color in the RGB spectrum that corresponds to the value. So for
> example in the matrix above the biggest number which is 0.00966 (at
> position 1 , 1) could be set to RED and the smallest number which is
> 5.0084 (at position 6, 5) can be set to BLUE and all the other numbers
> be shades on a scale of Red going to Blue.
>
> I hope this problem makes sense. I am rather new to R and was
> wondering if there was a function or solution to this problem out
> there.
>
Hi Kartik,
Have a look at color2d.matplot in the plotrix package.
Jim
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