Trying to make a stacked histogram, but it just comes out grey, with no stacking. I don't understand what is different from all the examples on here, or the built in 'iris' example, unless using time as x variable is a problem.

I have a big df, in long format, cut down to 25 rows and named 'mini' for this example:

> dput(mini)
structure(list(maxdep = c(203.9540564, 212.9573869, 13.45896065, 
209.961431, 162.9633891, 13.97961439, 85.48389032, 102.4905817, 
100.0035986, 88.02608837, 89.02947373, 22.0301996, 20.03060219, 
19.03098037, 29.03141345, 13.03170014, 82.0328164, 55.03384725, 
15.03437183, 17.53463412, 37.5352136, 70.03588457, 90.53687883, 
91.53861116, 10.03902594), st_time = structure(c(1633321800, 
1633328510, 1633331050, 1633331285, 1633334080, 1633347960, 1633348185, 
1633355115, 1633279830, 1633298825, 1633301480, 1633302985, 1633303300, 
1633303600, 1633303825, 1633304280, 1633304430, 1633305635, 1633306445, 
1633306610, 1633306890, 1633307310, 1633307960, 1633309380, 1633310320
), class = c("POSIXct", "POSIXt"), tzone = ""), dbin = c(2, 2, 
1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
1, 1)), row.names = c(NA, 25L), class = "data.frame")

the code is simple:

gg3 <- ggplot(data = mini, aes(x = st_time, fill = dbin)) # 
gg3 <- gg3   geom_histogram(position = "stack", binwidth = 3600) # gives hourly columns in histogram
gg3

this should plot the start time of the data on the x axis - correct, against the count on y - correct and stack in colour by dbin value (e.g. 1 through 5) - producing 5 colours of histogram stacked on top of each other (only two are present in the sample data above).

Instead I get one grey plot of all data (25 count total). please help me understand what is wrong

CodePudding user response：

You can change dbin to a factor:

mini %>% 
  ggplot(aes(x = st_time, fill = as.factor(dbin) ))  
  geom_histogram(position = "stack", binwidth = 3600)