I am making multiple plots, that contain the same 4 discrete values, unknown, Negative, Neutral, Positive.
However not all of the data sets contain all the discrete values, and as such
in plot 1, unknown = yellow
in plot 2, unknown = purple, etc...
How can I set it so that, unknown allways = yellow, negative = purple...
below is the code i am using
library(viridis)
p <- ggplot() +
geom_polygon(data = spdfMelbSent_fortified2.1, aes(fill = sentiment, x = long, y = lat, group = group) , size= 0, alpha=1) +
theme_void() +
scale_fill_viridis(discrete = TRUE, breaks=c('unknown','Negative','Neutral','Positive'), name="sentiment", guide = guide_legend( keyheight = unit(3, units = "mm"), keywidth=unit(12, units = "mm"), label.position = "bottom", title.position = 'top', nrow=1) ) +
labs(
title = "Melbourne and Geelong",
subtitle = "Sentiment 27th April"
) +
theme(
text = element_text(color = "#22211d"),
plot.background = element_rect(fill = "#f5f5f2", color = NA),
panel.background = element_rect(fill = "#f5f5f2", color = NA),
legend.background = element_rect(fill = "#f5f5f2", color = NA),
plot.title = element_text(size= 22, hjust=0.01, color = "#4e4d47", margin = margin(b = -0.1, t = 0.4, l = 2, unit = "cm")),
plot.subtitle = element_text(size= 17, hjust=0.01, color = "#4e4d47", margin = margin(b = -0.1, t = 0.43, l = 2, unit = "cm")),
plot.caption = element_text( size=12, color = "#4e4d47", margin = margin(b = 0.3, r=-99, unit = "cm") ),
legend.position = c(0.7, 0.09)
) +
coord_map()
p
I'm just copying my comment as an answer to mark this question as answered.
It seems like you are missing a limits in your fill scale, which defines possible values and their order.
Adding limits = c("unknown", "Negative", "Neutral", "Positive") inside the scale_fill_viridis() call could solve the inconsistencies across multiple plots where one or more levels have been dropped.