title: My data seems to be structured incorrectly when making a plot
body: <p>I have posted about this graph before but I am getting the same issue and I think it may be due to my data set. This is what I am working from: </p>
  
  <pre><code>
  Date
  Surface
  
               Surface    pH     Temperature
  1   2019-05-13  12.08   8.56    11.16
  2   2019-05-29  11.68   8.90    8.76
  3   2019-06-10  8.69    9.07    14.65
  4   2019-06-24  2.26    7.49    17.51
  5   2019-07-08  4.54    7.77    23.82
  6   2019-08-05  2.13    8.17    25.29
  7   2019-08-19  6.34    8.62    26.50
  8   2019-09-04  9.33    9.03    24.31
  9   2019-09-16  10.98   8.58    21.02
  10  2019-09-30  9.59    8.61    17.33
  11  2019-10-14  16.07   8.70    10.39
  12  2019-11-14  9.12    8.07    6.38
  
  </code></pre>
  
  <p>When I produce a graph with this data set, I end up with a graph that is clearly not right and the y-axis is all over the place. </p>
  
  <pre><code>dat.g &lt;- gather(Plaster_2019_Data, type, value, -Date)
  
  ggplot(dat.g, aes(Date, value)) + 
    geom_bar(aes(fill = Date), stat = 'identity', position = "dodge2") +
    facet_grid(.~type) +
    expand_limits(y = c(1,30))
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/qKA1p.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qKA1p.png" alt="Graph with the wrong y axis"></a></p>
  
  <p>Another user created this code and made their own data set with my data: </p>
  
  <pre><code>
  df&lt;-structure(list(Date = structure(c(3L, 4L, 5L, 6L, 7L, 9L, 8L, 
                                    12L, 10L, 11L, 1L, 2L), .Label = c("10/14/2019", "11/14/2019", 
                                                                       "5/13/2019", "5/29/2019", "6/10/2019", "6/24/2019", "7/8/2019", 
                                                                       "8/19/2019", "8/5/2019", "9/16/2019", "9/30/2019", "9/4/2019"
                                    ), class = "factor"), Surface = c(12.08, 11.68, 8.69, 2.26, 4.54, 
                                                                      2.13, 6.34, 9.33, 10.98, 9.59, 16.07, 9.12), pH = c(8.56, 8.9, 9.07, 7.49, 7.77, 8.17, 8.62, 9.03, 8.58, 8.61, 8.7, 8.07), Temperature = c(11.16,8.76, 14.65, 17.51, 23.82, 25.29, 26.5, 24.31, 21.02, 17.33,                                                                                                                                                                                             10.39, 6.38)), class = "data.frame", row.names = c(NA, -12L))
  
  df$Date &lt;- as.Date(df$Date, format = "%m/%d/%Y")
  
  dat.g &lt;- gather(df, type, value, -Date)
  
  ggplot(dat.g, aes(Date, value)) + 
    geom_bar(aes(fill = type), stat = 'identity', position = "dodge2") +
    facet_grid(.~type) +
    expand_limits(y = c(1,30))+
    scale_x_date(date_breaks = "month",
                 date_labels = "%b")+
    theme(axis.text.x = element_text(angle = 45, hjust = 1))
  </code></pre>
  
  <p>This produces the correct graph. The bars are where they should be and the y axis is in the correct order. </p>
  
  <p><a href="https://i.stack.imgur.com/kM3wS.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/kM3wS.png" alt="Correct Graph"></a></p>
  
  <p>I would love some help figuring out why my data set is not working correctly!</p>