I am having trouble adding data labels to points in a reactive scatterplot. I cannot find any information online or in previous questions. Either the length is incorrect or I am referencing the wrong object.

df <- structure(list(Date = structure(c(19949, 19949, 19949, 19949, 
                                        19956, 19956, 19962, 19962, 19977, 19977, 19977, 19977, 19985, 
                                        19985, 19991, 19991, 19991, 19991, 19997, 19997), class = "Date"), 
                     Unit = structure(c(1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 1L, 1L, 
                                        2L, 2L, 2L, 2L, 1L, 1L, 2L, 2L, 2L, 2L), levels = c("A", 
                                                                                            "B"), class = "factor"), Species = structure(c(1L, 2L, 1L, 
                                                                                                                                           2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 
                                                                                                                                           1L, 2L), levels = c("Dunlin", "Willet"), class = "factor"), 
                     Tally = c(0L, 8L, 0L, 44L, 0L, 15L, 0L, 27L, 0L, 6L, 0L, 
                               10L, 6L, 16L, 0L, 3L, 0L, 14L, 0L, 18L)), row.names = c(NA, 
                                                                                       20L), class = "data.frame")


# Define ui
ui <- fluidPage(
  dateRangeInput(inputId = "Date", label = "Date Range",start = min(df$Date),end=max(df$Date),min = min(df$Date),max=max(df$Date)),
  selectInput(inputId = "Species", 
              label = "Choose Species", 
              choices = unique(df$Species),
              selected = 'Dunlin'),  
  checkboxGroupInput(inputId = "Unit", 
                     label = "Choose Units", 
                     choices = unique(df$Unit),
                     selected = 'B'),
  plotOutput("line"))

# Define server
server <- function(input, output) {
  filtered_data <- reactive({
    df %>%
      filter(Species == input$Species, Unit %in% input$Unit, between(Date ,input$Date[1], input$Date[2]))})
  
  output$line <- renderPlot({
    ggplot(filtered_data(), aes(x = Date, y = Tally, color = Unit, group = Unit)) +
      geom_line() +
      geom_point() +
      geom_text(label=input$Tally, check_overlap = T) +
      scale_x_date(date_breaks = "2 weeks" , date_labels = "%d-%b") 
  })
}

shinyApp(ui = ui, server = server)

I am having trouble adding data labels to points in a reactive scatterplot. I cannot find any information online or in previous questions. Either the length is incorrect or I am referencing the wrong object.

df <- structure(list(Date = structure(c(19949, 19949, 19949, 19949, 
                                        19956, 19956, 19962, 19962, 19977, 19977, 19977, 19977, 19985, 
                                        19985, 19991, 19991, 19991, 19991, 19997, 19997), class = "Date"), 
                     Unit = structure(c(1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 1L, 1L, 
                                        2L, 2L, 2L, 2L, 1L, 1L, 2L, 2L, 2L, 2L), levels = c("A", 
                                                                                            "B"), class = "factor"), Species = structure(c(1L, 2L, 1L, 
                                                                                                                                           2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 
                                                                                                                                           1L, 2L), levels = c("Dunlin", "Willet"), class = "factor"), 
                     Tally = c(0L, 8L, 0L, 44L, 0L, 15L, 0L, 27L, 0L, 6L, 0L, 
                               10L, 6L, 16L, 0L, 3L, 0L, 14L, 0L, 18L)), row.names = c(NA, 
                                                                                       20L), class = "data.frame")


# Define ui
ui <- fluidPage(
  dateRangeInput(inputId = "Date", label = "Date Range",start = min(df$Date),end=max(df$Date),min = min(df$Date),max=max(df$Date)),
  selectInput(inputId = "Species", 
              label = "Choose Species", 
              choices = unique(df$Species),
              selected = 'Dunlin'),  
  checkboxGroupInput(inputId = "Unit", 
                     label = "Choose Units", 
                     choices = unique(df$Unit),
                     selected = 'B'),
  plotOutput("line"))

# Define server
server <- function(input, output) {
  filtered_data <- reactive({
    df %>%
      filter(Species == input$Species, Unit %in% input$Unit, between(Date ,input$Date[1], input$Date[2]))})
  
  output$line <- renderPlot({
    ggplot(filtered_data(), aes(x = Date, y = Tally, color = Unit, group = Unit)) +
      geom_line() +
      geom_point() +
      geom_text(label=input$Tally, check_overlap = T) +
      scale_x_date(date_breaks = "2 weeks" , date_labels = "%d-%b") 
  })
}

shinyApp(ui = ui, server = server)

• r
• shiny

• Welcome to SO! To label each data point according to the value in the Tally column use geom_text(aes(label = Tally), ...). If that isn't your desired result please clarify what you are trying to achieve. – stefan Commented Mar 20 at 14:53

1 Answer 1

You are currently trying to use input$Tally but that object doesn't exist - input$ values are created by *Input functions like the selectInput but you do not have an *Input function with an id of Tally.

You are creating a subset of your data as filtered_data and this is the object that you should use to add labels to the plot. If you switch to using geom_text(label=filtered_data()$Tally, check_overlap = T) it will work, but as Stefan points out geom_text(aes(label=Tally), check_overlap = T) is the tidier way.