Better line graphs for hydrologic data. See the blog https://wordpress.com/post/tonyladson.wordpress.com/10384

Line_graph.R

######################################################################################
#
# Better line graphs for hydrologic data
#
#
#######################################################################################


library(tidyverse)
library(scales)
library(RColorBrewer)


# Create a data frame with some example data

dog_ck <- tribble(
  ~creek_name, ~duration, ~peak_flow,
  'Brown Dog Ck', 9, 1200,
  'Brown Dog Ck', 12, 1300,
  'Brown Dog Ck', 24, 1550,
  'Brown Dog Ck', 36, 1420,
  'Brown Dog Ck', 48, 1400,
  'Brown Dog Ck', 72, 1500,
  'Long Ck', 9, 100,
  'Long Ck', 12, 100,
  'Long Ck', 24, 100,
  'Long Ck', 36, 70,
  'Long Ck', 48, 60,
  'Long Ck', 72, 60,
  'Short Ck', 9, 700,
  'Short Ck', 12, 620,
  'Short Ck', 24, 800,
  'Short Ck', 36, 800,
  'Short Ck', 48, 820,
  'Short Ck', 72, 900,
  'Rocky Ck', 9, 400,
  'Rocky Ck', 12, 520,
  'Rocky Ck', 24, 500,
  'Rocky Ck', 36, 450,
  'Rocky Ck', 48, 420,
  'Rocky Ck', 72, 400,
  'Reedy Ck', 9, 490,
  'Reedy Ck', 12, 550,
  'Reedy Ck', 24, 500,
  'Reedy Ck', 36, 540,
  'Reedy Ck', 48, 510,
  'Reedy Ck', 72, 600,
  'Waterhole Ck', 9, 320,
  'Waterhole Ck', 12, 320,
  'Waterhole Ck', 24, 490,
  'Waterhole Ck', 36, 450,
  'Waterhole Ck', 48, 420,
  'Waterhole Ck', 72, 300)


# Change the Creek names to factors.
# if we use forcats::as_factor the order of the factors will match the order of appearance in the data frame.

dog_ck <- dog_ck %>% 
  mutate(creek_name = forcats::as_factor(creek_name, ordered = TRUE))

###########################################################################################
#
# First version of the line graph

# Choose an inappropriate colour palatte

mypalette <- RColorBrewer::brewer.pal(8,"Blues")


dog_ck %>%  
  ggplot(aes(factor(duration), peak_flow, group = creek_name, colour = creek_name)) +
  geom_point() +
  geom_line() +
  scale_color_manual(name = '', 
                     values = mypalette[3:8]) +
  scale_y_continuous(name = 'Peak flow') +
  scale_x_discrete(name = 'Duration (h)') +
  theme_bw()

###########################################################################################
#
# Second and better version of the line graph


my_colours <- RColorBrewer::brewer.pal(6, 'Dark2') # distinct colours


improved_plot <- dog_ck %>% 
  ggplot(aes(duration, peak_flow, colour = creek_name)) +
  geom_point() +
  geom_line()  +
  scale_colour_manual(guide = FALSE, values = my_colours) +
  scale_y_continuous(name = 'Peak flow (cumec)', labels = comma) + # comma separators
  scale_x_continuous(name = 'Duration (h)', limits = c(NA, 90), breaks = c(9, 12, 24, 36, 48, 72),  # natural scaling for x-axis
                     minor_breaks = FALSE) +
  annotate(geom = 'text',   # label both ends of the lines.  I
           x = 75, 
           y = 1500,
           label = 'Brown Dog Ck',
           hjust = 'left',
           colour = my_colours[1]) +
  annotate(geom = 'text',
           x = 5, 
           y = 1170,
           label = 'Brown Dog Ck',
           hjust = 'left',
           colour = my_colours[1]) +
  
  annotate(geom = 'text',
           x = 75, 
           y = 60,
           label = 'Long Ck',
           hjust = 'left',
           colour =  my_colours[2]) +
  annotate(geom = 'text',
           x = 5, 
           y = 60,
           label = 'Long Ck',
           hjust = 'left',
           colour =  my_colours[2]) +
  annotate(geom = 'text',
           x = 75, 
           y = 900,
           label = 'Short Ck',
           hjust = 'left',
           colour = my_colours[3]) +
  annotate(geom = 'text',
           x = 0, 
           y = 750,
           label = 'Short Ck',
           hjust = 'left',
           colour = my_colours[3]) +
  annotate(geom = 'text',
           x = 75, 
           y = 400,
           label = 'Rocky Ck',
           hjust = 'left',
           colour = my_colours[4]) +
  annotate(geom = 'text',
           x = -3, 
           y = 400,
           label = 'Rocky Ck',
           hjust = 'left',
           colour = my_colours[4]) +
  annotate(geom = 'text',
           x = 75, 
           y = 600,
           label = 'Reedy Ck',
           hjust = 'left',
           colour = my_colours[5]) +
  annotate(geom = 'text',
           x = -3, 
           y = 500,
           label = 'Reedy Ck',
           hjust = 'left',
           colour = my_colours[5]) +
  annotate(geom = 'text',
           x = 75, 
           y = 300,
           label = 'Waterhole Ck',
           hjust = 'left',
           colour = my_colours[6]) +
  annotate(geom = 'text',
           x = 0, 
           y = 290,
           label = 'Waterhole Ck',
           hjust = 'left',
           colour = my_colours[6])

improved_plot # print the graph

  


###########################################################################################
#
# Minimalist version

improved_plot + 
  theme_bw() +
  theme(panel.grid.major = element_blank(),  # turn off the grid lines
        panel.grid.minor = element_blank(),
        panel.border = element_blank()) # turn off the border


# To retain the axes

improved_plot + 
  theme_bw() +
  theme(panel.grid.major = element_blank(),  # turn off the grid lines
        panel.grid.minor = element_blank(),
        panel.border = element_blank(), # turn off the border
        axis.line = element_line( colour = 'black')) # draw axes