I'm trying to produce a figure in black and white with geom_sf. I have seven categories so I want to make some of them patterned (rather than just shades of grey). But I can't seem to get geom_sf into black and white mode even to begin with. Any advice? Below is the code (category denotes which of the seven categories each geographic unit belongs to).
fig <- ggplot(data = d)+
geom_sf(aes(fill = category))+
theme_bw()