Dear All,

I am trying the plot a correlation heat matrix to show that the sample preparation method does not have a bias based on some measurements. The correlation is very high among all the samples. Therefore, in order to pick the best correlation visually, I would like to do a heatmap. As the samples are highly correlated (all values above 0.94), I am not able to show the differences in the heatmap.

```
corr = 1.00 0.99 0.94
0.99 1.00 0.97
0.94 0.97 1.00
```

I am using corrplot

```
library(corrplot)
corrplot(as.matrix(corr),method="shade",is.corr=T,col=colorRampPalette(brewer.pal(9,"Blues"))(100))
```

I would like to see that 0.99 is different from 0.94 in the graph. Also I think would be great to have the color scale only for positive correlation (0 to 1). Any help would be highly appreciated in deciding a color palette or with alternate methods for this purpose. Thanks!

You might be interested in a correlogram, such as those offered by the

`corrgram`

R package