Drill Down Maps In R + Shiny - r

Question

I want to implement drill down heat map of USA.
Something like : Highchart link
But I want to display my own data in the given drill down heat map in
R + shiny.
I am unable to understand how to get my data to work with the given example. I was able to implement the given example on R shiny but I don't know how to get my own data for states and county .
I have data in excel format which I want to show on the maps.
I am relatively new to JS and CSS , I think the challenge is in this only.
I have no knowledge of AJAX , and if it can be implemented without it then it would be great.
Someone suggested me to use JSON file to import my own data , but I cannot do it.

Answer 1

There is now an R package "leafdown" available on github, which provides drilldown functionality. It can be found here: https://hoga-it.github.io/leafdown/index.html.
A basic example:
devtools::install_github("hoga-it/leafdown")
library(leafdown)
library(leaflet)
library(shiny)
library(dplyr)
library(shinyjs)
ger1 <- raster::getData(country = "Germany", level = 1)
ger2 <- raster::getData(country = "Germany", level = 2)
ger2#data[c(76, 99, 136, 226), "NAME_2"] <- c(
"Fürth (Kreisfreie Stadt)",
"München (Kreisfreie Stadt)",
"Osnabrück (Kreisfreie Stadt)",
"Würzburg (Kreisfreie Stadt)"
)
spdfs_list <- list(ger1, ger2)
ui <- shiny::fluidPage(
tags$style(HTML(".leaflet-container {background: #ffffff;}")),
useShinyjs(),
actionButton("drill_down", "Drill Down"),
actionButton("drill_up", "Drill Up"),
leafletOutput("leafdown", height = 600),
)
# Little helper function for hover labels
create_labels <- function(data, map_level) {
labels <- sprintf(
"<strong>%s</strong><br/>%g € per capita</sup>",
data[, paste0("NAME_", map_level)], data$GDP_2014
)
labels %>% lapply(htmltools::HTML)
}
server <- function(input, output) {
my_leafdown <- Leafdown$new(spdfs_list, "leafdown", input)
update_leafdown <- reactiveVal(0)
observeEvent(input$drill_down, {
my_leafdown$drill_down()
update_leafdown(update_leafdown() + 1)
})
observeEvent(input$drill_up, {
my_leafdown$drill_up()
update_leafdown(update_leafdown() + 1)
})
output$leafdown <- renderLeaflet({
update_leafdown()
meta_data <- my_leafdown$curr_data
curr_map_level <- my_leafdown$curr_map_level
if (curr_map_level == 1) {
data <- meta_data %>% left_join(gdp_2014_federal_states, by = c("NAME_1" = "Federal_State"))
} else {
data <- meta_data %>% left_join(gdp_2014_admin_districts, by = c("NAME_2" = "Admin_District"))
}
my_leafdown$add_data(data)
labels <- create_labels(data, curr_map_level)
my_leafdown$draw_leafdown(
fillColor = ~ colorNumeric("Blues", GDP_2014)(GDP_2014),
weight = 2, fillOpacity = 0.8, color = "grey", label = labels,
highlight = highlightOptions(weight = 5, color = "#666", fillOpacity = 0.7)
) %>%
addLegend("topright",
pal = colorNumeric("Blues", data$GDP_2014),
values = data$GDP_2014,
title = "GDP per capita (2014)",
labFormat = labelFormat(suffix = "€"),
opacity = 1
)
})
}
shinyApp(ui, server)