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rggplot2gganimate

gganimate error with long-format data and plot_usmap

I'm trying to animate a map graph using gganimate but am running into the following error:

Error in seq.default(range[1], range[2], length.out = nframes) : 
'from' must be a finite number

It seems like this usually occurs when the variable used for transition_time() isn't numeric or the data's in the wrong form, but I don't know how that could be in my case; my data's in the proper long format and the variable for transition_time() is numeric and always finite.

Is this a specific issue with plot_usmap()? Am I missing something obvious?

My data is on GitHub. Code below:

library("usmap")
library("ggplot2")
library("gganimate")

load("helpdata.Rda")

check = plot_usmap(data = df_map, values = "frac_cov") +
  scale_fill_stepsn(breaks=c(-100, 0, 0.1, 0.2, 0.3, 0.4, 0.5,
                             0.6, 0.7, 0.8, 0.9, 1, 100),
                    colors=c("red", "gray100", "gray90", "gray80", "gray70", "gray60",
                             "gray50", "gray40", "gray30", "gray20", "gray10", "red"),
                    na.value="white") +
  labs(fill = "", title = "Fraction of excess deaths\nattributed to COVID-19") +
  theme(legend.position = "right", plot.title = element_text(hjust = 0.5)) +
  transition_time(month)

anim <- animate(check, nframes=9, fps=1)

Thanks so much!

Solution

  • Your dataset has 50 unique fips values. The map data in the usmap package comes with 51. When plot_usmap creates the ggplot layers, it merged your dataset with the map data by fips code, which adds on NA values to the month column since one of the fips codes has no match.

    (transition_time makes a fuss about this while transition_state doesn't. I'm not familiar enough with the gganimate package to theorize why that's the case.)

    Add the following to your dataset before plotting. It should solve the problem:

    df_map <- rbind(df_map,
                data.frame(month = sort(unique(df_map$month)),
                           frac_cov = 0,
                           fips = 11)) # the missing fips value

    Result after running the same animation code shown in the question:

    map