Remove ticks / tiny white line from colorbar ggplot2

Question

how to remove that white line from a ggplot2 colourbar?

ggplot(faithfuld, aes(waiting, eruptions)) +
  geom_raster(aes(fill = density)) +
  scale_fill_gradientn(colours = terrain.colors(10))+
theme(legend.key.height=unit(2,"line"))

generates this plot

But if you zoom in the legend, you will see tiny annoying white lines:

How can I remove them? Thanks

Answer 1

You can set the ticks.colour= within guide_colorbar() by referencing via guides()... here ya go:

# where "plot" = your plot code...
plot + guides(fill=guide_colorbar(ticks.colour = "black"))

And to remove them, set the color to NA:

plot + guides(fill=guide_colorbar(ticks.colour = NA))