ggplot not showing - area is blank - r

Question

I am relatively new to ggplot2 and I have created a plot based on a csv file.
The problem I am having is that the plot is blank:
Nothing shows expect the title and I am not sure why!
As you can see the data is fine within RStudio:
My csv file is in the same directory as my app.R file:
My working directory is the same folder:
So why is ggplot2 failing to pick up the data held within the csv file?
Here is my code:
library(shiny)
library(ggplot2)
ui <- (fluidPage(
titlePanel("Pig Breeding")
)
)
mainPanel(
plotOutput(outputId = "scatterplot")
)
server <- (function(input, output){
output$scatterplot <- renderPlot({
pig_plot <- ggplot(read.csv("pigs_data.csv"),
aes_string(x = "species", y = "sow_count") +
geom_point())
})
})
shinyApp(ui, server)

Answer 1

the below code works with a test data called iris. Your mistake lies in your
ui <- (fluidPage(
titlePanel("Pig Breeding")
)
)
mainPanel(
plotOutput(outputId = "scatterplot")
)
ui code. You have left your mainPanel out of the fluidpage parenthesis. Thus, it does not read the plotOutput.
Example
library(shiny)
# Define UI for application
ui <- fluidPage(
# Application title
titlePanel("Iris data"),
# Show a plot of the generated distribution
mainPanel(
plotOutput("distPlot")
)
)
# Define server logic
server <- function(input, output) {
output$distPlot <- renderPlot({
ggplot(iris, aes(x=Sepal.Width, y=Petal.Width)) + geom_point()
})
}
# Run the application
shinyApp(ui = ui, server = server)
The code below should work for your question.
library(shiny)
# Define UI for application
ui <- fluidPage(
# Application title
titlePanel("Pig Breeding"),
# Show a plot of the generated distribution
mainPanel(
plotOutput("scatterplot")
)
)
# Define server logic
server <- function(input, output) {
output$scatterplot <- renderPlot({
ggplot(read.csv("pigs_data.csv"),
aes(x = "species", y = "sow_count")) + geom_point()
})
}
# Run the application
shinyApp(ui = ui, server = server)