ggbiplot - change the group color and marker
<p>In the example ggbiplot script plot there are 3 groups, how can I change the marker colors and shapes?</p>

<pre><code>library(ggbiplot)
data(wine)
wine.pca &lt;- prcomp(wine, scale. = TRUE)
ggbiplot(wine.pca, obs.scale = 1, var.scale = 1, group=wine.class,
         varname.size = 3, labels.size=3, 
         ellipse = TRUE, circle = TRUE) +
  scale_color_discrete(name = '') +  
  geom_point(aes(colour=wine.class), size = 3) +
  theme(legend.direction ='horizontal', 
        legend.position = 'top')
</code></pre>