RE: Help with creating a reactive Leaflet and R Shiny App

shiny
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1

Hi Everyone!

I am currently creating a Shiny app using a combination of the R Leaflet and R Shiny packages. I am able to create a static map but I am having trouble with making my map interactive. I am very new to both this community and coding so please bare with me.

I think I know exactly where my code is having trouble and I have been trying to trouble shoot it for the past day but I feel like I am running into a brick wall repeatedly. I believe I have provided everything in this post.

The Data:

  1. Vancouver's Shape Files (I downloaded the whole ShapeFile Data set in "Export"):
    Local area boundary — City of Vancouver Open Data Portal

In my code this is "vancouver "

  1. Vancouver's 2016 Census Data:
    I made some changes to the census data, and the file I used is this:
    Census_all_flip - Google Sheets

In my code this is "census_all "

(I downloaded the "Census local area profiles 2016 (CSV)")
Source Data: Census local area profiles 2016 — City of Vancouver Open Data Portal

My code:

## Library of installed packages
library(leaflet)
library(magrittr)
library(sf)
library(geojsonio)
library(htmltools)
library(htmlwidgets)
library(stringi)
library(RColorBrewer)
library(shiny)
library(shinyWidgets)

# I read the shape file of vancouver's local-area-boundary
vancouver <- read_sf('~/Desktop/local-area-boundary/local-area-boundary.shp')


census_all <- read.csv('~/Desktop/Census_all_flip.csv')

#
is.element(census_all$name, vancouver$name) %>%
  all()

# Merging vancouver with census data
vancouver <- merge(vancouver, census_all, by = 'name', all.x = F)

paletteNum <- colorNumeric('Blues', domain = NULL)


# Labeling

vancouverLabels <- sprintf('<b>%s</b><br/>%g people',
                           vancouver$name, vancouver$X0.to.14.years) %>%
  lapply(function(x) HTML(x))

vancouver <- cbind(vancouver, matrix(vancouverLabels, ncol = 1, dimnames = list(c(), c('vancouverLabels'))))


# Integrating Leaflet with Shiny
ui <- fluidPage(
  
  # Title
  titlePanel("Census Data"),
  
  #Leaflet Map
  leafletOutput("mymap"),
  
  absolutePanel(
    pickerInput(
      inputId = "agegroup",
      label = "Select an Age Group",
      choices = c("X0.to.14.years", "X0.to.4.years", "X5.to.9.years", "X10.to.14.years", "X15.to.64.years")),
  )

  
  )

server <- function(input, output, session) {
  
  ## (SOMETHING WRONG HERE)
  filteredData <- reactive({
    vancouver[input$agegroup,]
  })
  
  ## (SOMETHING WRONG HERE)
  # This reactive expression represents the palette function,
  # which changes as the user makes selections in UI.
  paletteNum<- reactive({
    colorNumeric('blues', vancouver[input$agegroup,])
  })
  
  
  output$mymap <- renderLeaflet({
    leaflet() %>%
      addProviderTiles(providers$CartoDB.PositronNoLabels) %>% 
      setView(lng = -123.11934, lat = 49.24966, zoom = 11) %>% 
      addPolygons(data = vancouver,
                  color = 'white',
                  weight = 1,
                  smoothFactor = .3,
                  fillOpacity = .75,
                  fillColor = ~paletteNum(vancouver$X0.to.14.years),
                  label = ~vancouverLabels,
                  labelOptions = labelOptions(
                    style = list(color = 'gray30'),
                    textsize = '10px'),
                  highlightOptions = highlightOptions(
                    weight = 3,
                    color = 'dodgerblue'
                  )
      ) %>% 
      addLegend(pal = paletteNum, values = vancouver$X0.to.14.years,
                title = '<small>2016 Vancouver Census Data <br> Population: Ages 0 to 14 </small>',
                position = 'bottomleft')
  })

}

shinyApp(ui, server)

I know I also need a reactive output with leafletProxy where my fillColor will update depending on which age group is selected, and also my legend, however, I feel super stuck with the code I have already. If anyone could provide some pointers I would be so grateful. I at sorry I cannot provide the data in an easier manner... I have tried and I think I made it worse trying to create a dummy dataframe to showcase this problem.

The problem I have ran into seems to be coming from my "filteredData" and "paletteNum" functions but I have no clue what I am doing wrong even though I know something is wrong.