Quality Control visualizations

[chenqing1991]

Hi，I have just learned the scRNA-seq_online course，I have a question

when you visualiza the UMI counts (transcripts) per cell by code as bellow:

Visualize the number UMIs/transcripts per cell

metadata %>%
ggplot(aes(color=sample, x=nUMI, fill= sample)) +
geom_density(alpha = 0.2) +
scale_x_log10() +
theme_classic() +
ylab("Cell density") +
geom_vline(xintercept = 500)

I'm wonder should the xintercept parameter changed by log10( )? Just as this : +geom_vline(xintercept = log10(500))

Thanks very much!