title: R - How to 'create' or plot missing data?
body: <p>I have a datset, AIS_dat, which looks at the number of boats (BoatCount) present at three sites (Site) on different days of the week (Day), before and during a Covid lockdown.</p>
  <pre><code>rm(list = ls())
  setwd('K:/SoundTrap/Boats/PSD Output/Duty cycle data/TOL analysis')
  getwd()
  
  AIS_dat&lt;-read.csv(&quot;AllSitesConcat_dBcalcs_50-24000Hz_matchedCameraCounts.csv&quot;) 
  str(AIS_dat)
  
  #set factors
  AIS_dat$Lockdown &lt;- as.factor(AIS_dat$Lockdown)
  
  #change order of sites
  AIS_dat$Site&lt;-factor(AIS_dat$Site, 
                       level=c('Kawau','Tiritiri','Noises'))
  
  #change order of days
  AIS_dat$Day&lt;-factor(AIS_dat$Day, 
                       level=c('Mon','Tue','Wed','Thu','Fri','Sat','Sun'))
  
  #hour of day as factor
  AIS_dat$Hour &lt;- as.factor(AIS_dat$Hour)
  
  
  #Look at variation between sites
  bp&lt;-ggplot(AIS_dat, aes(x=Day,y=BoatCount,fill=factor(Site))) +
    geom_boxplot()+
    ylab(expression(&quot;Number of Boats&quot;))+
    xlab(&quot;Day of Week&quot;)+
    scale_fill_manual(values = get_pal(&quot;Kereru&quot;),
                      name=&quot;Site&quot;) +
    theme_bw()
  bp
  
  bp&lt;-bp+theme(axis.text.x = element_text(angle = 0,size=14),
               axis.text.y = element_text(size=14),
               axis.title.x = element_text(size=14),
               axis.title.y =element_text(size=14),
               #legend.title = element_text(size = 14),
               #legend.text = element_text(size = 14)
                ) #rotate x-axis labels
  
  bp&lt;-bp+facet_grid(rows=vars(Lockdown)) #separate plot for each season
  bp
  </code></pre>
  <p>The plot looks like <a href="https://i.stack.imgur.com/K0Pbz.png" rel="nofollow noreferrer">this</a></p>
  <p>...which is awesome. BUT, because there is no data for Tiritiri under 'During', we only see two sites, and it is a bit misleading as the order of the sites then changes. I'd like to have missing data in this panel to make it clear which site is which. How would I do this? Would I have to add missing data to my original datasheet somehow? I tried this but it didn't work, so if that is the best approach I am not sure which way to do it?</p>
  <p>The dataset looks like <a href="https://i.stack.imgur.com/DwvqY.png" rel="nofollow noreferrer">this</a> (but has 17143 rows):</p>