闪亮的初学者 - ggplot geom_tile 的问题答案

【问题标题】：Begginer in Shiny - Problems with ggplot geom_tile闪亮的初学者 - ggplot geom_tile 的问题
【发布时间】：2021-03-05 13:38:54
【问题描述】：

我正在尝试在 R 中使用 ggplot 和 Shiny 制作热图，但该图未按预期显示。我使用的数据结构与 Shiny-RStudio 示例不同，也许这就是我没有得到好的结果的原因。

我的数据表包含 152013 行和 7 个变量（区域、季节、周、fishingfleet、长度、类别、vul1.indicator）。我想用 x=week 和 y=zone 制作变量“vul1.indicator”的热图，闪亮的应用程序用户可以选择类别和季节。我的问题是，当我在侧边栏中更改“季节”和“类别”的选择时，只有图例发生了变化，情节没有变化。情节部分和选择之间似乎没有联系。我不知道我在哪里弄错了。你能帮帮我吗？

这是我的表格示例（“类别”有 10 个选项，“季节”有 3 个选项：

> Vul1MoyZoneAgr
    zone    season week fishingfleet length category vul1.indicator
1     Z1 2012-2013    1          CAD     T1   CAD-T1              1
2     Z1 2012-2013    2          CAD     T1   CAD-T1              1
3     Z1 2012-2013    3          CAD     T1   CAD-T1              1
4     Z1 2012-2013    4          CAD     T1   CAD-T1              1
5     Z1 2012-2013    5          CAD     T1   CAD-T1              1
6     Z1 2012-2013    6          CAD     T1   CAD-T1              1
7     Z1 2012-2013    7          CAD     T1   CAD-T1              1
8     Z1 2012-2013   46          CAD     T1   CAD-T1              1
9     Z1 2012-2013   47          CAD     T1   CAD-T1              1
10    Z1 2012-2013   48          CAD     T1   CAD-T1              1
11    Z1 2012-2013   49          CAD     T1   CAD-T1              1
12    Z1 2012-2013   50          CAD     T1   CAD-T1              1
13    Z1 2012-2013   51          CAD     T1   CAD-T1              1
14    Z1 2012-2013   52          CAD     T1   CAD-T1              1

这是我的代码：

library(ggplot2)
Vul1MoyZoneAgr <- read.table("C:/Users/user/Documents/Vul1MoyZoneAgr.txt", sep="\t",quote="", dec=",", header = TRUE)
Vul1MoyZoneAgr$zone <- factor(Vul1MoyZoneAgr$zone, levels = c("Z1", "Z2", "Z3", "Z4", "Z5", "Z6", "Z7", "Z8", "Z9", "Z10", "Z11", "Z12", "Z13", "Z14", "Z15", "ZI", "ZJ"))
Vul1MoyZoneAgr$week <- factor(Vul1MoyZoneAgr$week, levels = c("40","41", "42", "43", "44", "45", "46", "47", "48", "49", "50", "51", "52", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20"))
# Define UI ----
ui <- fluidPage(
    
    
    titlePanel("Vulnerability indicator"),
    
    
    sidebarLayout(
        
        sidebarPanel(
            
            selectInput("category", "category:", 
                        choices = c(unique(Vul1MoyZoneAgr$category))),
            selectInput("season", "season:",
                        choices = c(unique(Vul1MoyZoneAgr$season))),
            
            
        ),
        
        mainPanel(
            
            # Output: Formatted text for caption ----
            h3(textOutput("caption")),
            
            # Output ----
            
                plotOutput("vul1.indicatorPlot")

            
        )
    )
)

# Define server logic ----
server <- function(input, output) {

    # Compute the formula text ----
    # This is in a reactive expression since it is shared by the
    # output$caption and output$vul1.indicatorPlot functions
    formulaText <- reactive({
        paste("vulnerability indicator ~", input$category, "~", input$season)
})
    # Return the formula text for printing as a caption ----
    output$caption <- renderText({
        formulaText()
    })
    
    # Reactive expression for the data subsetted to what the user selected
    
    
   
    # Generate a plot of the requested season and category ----

    output$vul1.indicatorPlot <- renderPlot({
        ggplot(as.formula(formulaText()),
            data = Vul1MoyZoneAgr, mapping = aes(x=week, y=zone, fill=vul1.indicator)) + theme_bw() +
            geom_tile(aes(fill = vul1.indicator), colour = "white") + scale_fill_gradient(low = "#F2E8EC", high = "#990000", limits=c(0, 7), breaks=seq(0,7,by=1)) +
            labs(fill = "Vul. Ind.") +
            theme(strip.background = element_rect(colour="black", fill="white"), axis.text.x = element_text(face= "bold", size = 10), axis.text.y = element_text(face= "bold",size = 10), axis.title.x = element_text(face= "bold",size = 12), axis.title.y = element_text(face= "bold",size = 12), strip.text.y = element_text(face= "bold",size = 10),strip.text.x = element_text(face= "bold",size = 12), legend.text = element_text(face= "bold",size = 12), legend.title = element_text(face= "bold",size = 12), legend.key.size = unit(1.5, "cm"), legend.key.width = unit(0.5,"cm"), panel.grid.major=element_line(colour = "white"))
        })
    
}


shinyApp(ui, server)

谢谢！

【问题讨论】：

标签： r ggplot2 shiny reactive

【解决方案1】：

简短的回答是您在生成绘图时没有使用任何类型的反应值，即当您更改选择时，它不会改变绘图的计算方式。我的意思是你甚至已经有一个代码的注释部分，它的位置是空白的。

您需要一些类似于数据集的东西，当其中一个选择器更改时会更新：

displayData <- reactive( <code to subset data> )

然后在创建情节时使用它

ggplot(data = displayData()...

【讨论】：

【解决方案2】：

谢谢马库斯！现在可以了。

我使用了这个代码：

# Reactive expression for the data subsetted to what the user selected
    filteredData <- reactive({
        req(input$category, input$season)
        filter(Vul1MoyZoneAgr, category == input$category, season == input$season)
    
    })

然后：

ggplot(data = filteredData(), ...

【讨论】：