how to color points in 17 colors based on principal component?

Question

I am doing PCA in R on a data frame(df_f)

pc_gtex <- prcomp(df_f)

plot(pc_gtex$x[,1], pc_gtex$x[,2], col=gtex_group, main = "PCA", xlab = "PC1", ylab = "PC2")
legend("topleft", col=1:17, legend = paste(unique(gtex_pm$tissue), 1:17), pch = 20, bty='n', cex=1.5)

Below is my group table for the PCA.The sample column in this table actually represents the rows of the main data to be plotted.The columns of that table are genes.So basically I have 17 groups/tissues to be represented on PCA.

head(gtex_pm)

     sample   tissue

   1 SRR1069514 Prostate
   2 SRR1071717  Bladder
   3 SRR1073069 Prostate

Based on the above gtex_group object looks like the levels:

head(gtex_group)
[1] 1 2 1 1 1

THE sample head of Main table for PCA is :The rownames are the Samples

   SRR1069514   0   0.0009995   5.773065971 1.644998088 0.142367241 0.176471143 0.195566784 0.0009995   0.025667747 3.380994674 1.762502288 0   0.077886539 0   0.002995509 0.01093994  2.110576771 1.38829236  2.26186726  0.431132855 3.108480433 3.96347629  0   0   0.41012092  3.48452699  1.68565794  0   1.425034189 1.87456758  2.590542128 0   0   0   1.941471742 0.961646434 0   1.17711535  0.058268908 0   0.260824618 3.08534443  1.10426296  0.242946179 0.0009995   0   0   0   0.0009995   1.560247668 1.517541898 0.016857117 0.767326579 0.0009995   3.0191069   0   2.607050533 1.446683661 2.288384744 2.62082062  0.19309663  0   0   0.234281296 0   1.415610416 2.328837464 0.008959741 0.911479175 0.375005901 0.660107327 3.184739763 1.16064768  0.001998003 0.138891999 2.219855445 3.1011278   1.81872592  2.98229236  2.4114395   3.24528404  0   1.54734972  0.406131553 0.029558802 0.003992021 0.693647056 2.07581 2.8357982   0.0009995   0.082501222 1.09661029  2.75829962  0.635518068 3.11484775  0.01291623  3.40837159  0   
   SRR1071717   0   0   0.0009995   4.99519673  1.626491667 0.100749903 0.327863862 0.09531018  0   0.056380333 3.328196489 1.541373182 0   0.091667189 0.044973366 0   0.033434776 1.953311265 1.56444055  1.79142608  0.993622075 3.206236281 3.82609468  0   0   2.565487674 3.2202349   1.1304339   0   1.092258815 1.80203978  2.645394351 0   0   0.0009995   1.681200279 2.047434746 0   0.948176921 0.006975614 0.014888613 0.298622013 2.49667052  1.01884732  0.38662202  0   0   0   0   0.0009995   0.941958479 1.752845376 0.017839918 0.216722984 0.051643233 3.0505518   0   2.034444176 0.988053098 2.235804059 1.89686995  0.090754363 0   0   0.198850859 0   1.585554972 2.274905524 0   0.04305949  0.056380333 0.044016885 0.771496147 1.195436473 0   0.368801124 1.974636427 2.7700856   2.00120969  2.88875935  2.2651947   2.66242502  0   0.429181635 0.04018179  0.034401427 0   0.242161557 1.9907469   2.1384177   0.0009995   0.008959741 0.99916021  2.3892214   0.086177696 3.16821391  0   3.2038434   0
   SRR1073069   2.19544522  1.32866525  0.0009995   4.50198508  1.159707388 0.141499562 0.265436464 0.026641931 2.3330173   0.028587457 3.140698044 1.537297235 0.012916225 0.023716527 0   0.002995509 0.049742092 2.071157322 1.02460688  2.11818137  0.359072069 2.419656765 3.5065479   0.137149838 2.121902193 0.305276381 2.95958683  1.49939981  3.14397985  1.001366904 1.450911    1.39475844  1.930071085 1.140074079 0.037295785 1.609437912 0.412109651 0.870456196 0.943516718 0.013902905 0   0.152721087 2.88836976  1.482967248 0.272314595 2.061532121 0.552159487 2.394890764 1.391033116 0.443402947 1.593714952 1.285921387 0.00796817  0.371563556 0.020782539 3.1946651   1.26327891  2.212003715 1.46672161  2.140183804 2.71997877  0.294161039 0.018821754 0.0009995   0.179818427 1.893714192 1.731478538 2.502255288 0.013902905 0.752830183 0.347129531 0.407463111 2.467082065 0.558472277 1.563812734 0.022739487 1.608837732 2.8176816   1.30670988  2.44495233  1.81107178  3.03254625  0.569283193 0.948176921 0.101653654 0.036331929 0   0.786182047 1.9867779   3.5039946   2.463427618 0.008959741 0.76360564  2.20640453  0.514618422 2.87964779  1.11021142  3.18750899  1.22436349
   SRR1074410   2.69022562  1.70055751  0.013902905 3.314622273 0.503196597 0.4940863   0.044016885 0.023716527 1.753884517 0.03246719  2.767324893 1.666385193 0.009950331 0.05259245  0   0   0.017839918 1.575260461 0.76779072  2.22202559  0.83377831  2.198113071 3.57953881  0.051643233 2.207284913 0.072320662 3.04414141  1.39177929  2.851746423 0.982452934 1.33210213  1.888583654 1.871340532 1.238664044 0.03246719  1.734659877 0.486737828 0.412109651 1.126551657 0.035367144 0   0.213497174 2.76032635  1.131402111 0.572108852 2.102425378 0.291175962 1.85159947  0.943516718 0.283674051 1.232560261 0.982078472 0   0.223943232 0.035367144 2.9064091   1.583299255 2.376671636 1.185095749 2.07681309  2.20794469  0.877549904 0.151002874 0   0.107059072 3.038312721 1.486365915 2.633829402 0   0.403463105 0.195566784 0.285930539 1.296643139 0.48796633  1.664115474 0.054488185 1.884034745 2.3757426   1.71036863  2.61732284  1.9348492   3.1138708   1.220239777 0.322807874 0.12398598  0.004987542 0.002995509 0.446607051 1.939317    3.8484227   2.78346684  0.025667747 0.78253074  2.03352848  0.181487876 2.7091163   1.00430161  3.1429015   1.24875495

The figure eventually represents 8 colors and then repeats itself,so we cant distinguish between some tissues.I want to show 17 different colors.How do I do that?

It's much easier to help you if you provide a [reproducible example](http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example). Plus it's not easy choosing 17 different colors that are easily distinguishable. You might want to consult a graphic artist for that. — MrFlick, May 22 '15 at 20:38
I would have posted the picture,but I don't have the required 10 reputation for this.The down voting does not help either — user45292, May 22 '15 at 20:51
I suspect down-votes are due to non-reproducibility and lack of pictures (not your fault) in your question. Next time consider giving a well rounded question. Some instructions can be found [here](http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example). — Roman Luštrik, Jun 02 '15 at 11:16

score 0 · Accepted Answer · answered May 22 '15 at 20:34

0

It's hard to say without knowing exactly what your data look like, but perhaps something like this would work:

cols <- rainbow(17)[as.factor(gtex_pm$tissue)]

plot(pc_gtex$x[,1], pc_gtex$x[,2], col=cols, main = "PCA", xlab = "PC1", ylab = "PC2")

answered May 22 '15 at 20:34

C_Z_

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this does not work,it shows even fewer colors than before. – user45292 May 22 '15 at 20:43
@user45292 what does your df_f look like? – C_Z_ May 22 '15 at 22:34
df_f is the table that is the main table I pasted, with for rows beginning with SRR... – user45292 Jun 01 '15 at 14:59
Also,I added the labels after the plot. legend("topleft", col=1:17, legend = paste(unique(gtex_pm_tissue$tissue), 1:17), pch = 20, bty='n', cex=1.5).I see repetition of colors after 8 – user45292 Jun 01 '15 at 17:08

how to color points in 17 colors based on principal component?

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