问题
I am currently working in R and I am using leaflet package to vizualize geospatial data, I would like to make an analysis over the time and display my map given a time slider
In R there is the aesthetics function where it's possible to add slider with the frame
option, is there a similar function with leaflet/ggmap or at least is it possible to facet the map given different year.
I try to do the exercise with ggmap and ggplotly but this doesn't work as expected.
Any exemple/ document or hint to start would be very helpful
I have adapt an existing code in shiny to my data base, but I don't have any to perform kernel density estimation for each year
ui <- bootstrapPage(
tags$style(type = "text/css", "html, body {width:100%;height:100%}"),
leafletOutput("map", width = "100%", height = "100%"),
absolutePanel(top = 10, right = 10,
sliderInput("range", "Magnitudes", min(FINAL$UWY), max(FINAL$UWY),
value = range(FINAL$UWY), step = 1,
animate =
animationOptions(interval = 500, loop = TRUE)
),
#sliderInput("animation", "Looping Animation:",
# min = min(FINAL$UWY), max = max(FINAL$UWY),
# value = range(FINAL$UWY), step = 1,
# animate =
# animationOptions(interval = 300, loop = TRUE)
#),
selectInput("colors", "Color Scheme",
rownames(subset(brewer.pal.info, category %in% c("seq", "div")))
),
checkboxInput("legend", "Show legend", TRUE)
)
)
server <- function(input, output, session) {
# Reactive expression for the data subsetted to what the user selected
filteredData <- reactive({
FINAL[FINAL$UWY >= input$range[1] & FINAL$UWY <= input$range[2],]
})
# This reactive expression represents the palette function,
# which changes as the user makes selections in UI.
colorpal <- reactive({
colorNumeric(input$colors, FINAL$UWY)
})
output$map <- renderLeaflet({
# Use leaflet() here, and only include aspects of the map that
# won't need to change dynamically (at least, not unless the
# entire map is being torn down and recreated).
leaflet(FINAL) %>% addTiles() %>%
fitBounds(~min(longitude), ~min(latitude), ~max(longitude), ~max(latitude))
})
# Incremental changes to the map (in this case, replacing the
# circles when a new color is chosen) should be performed in
# an observer. Each independent set of things that can change
# should be managed in its own observer.
observe({
pal <- colorpal()
leafletProxy("map", data = filteredData()) %>%
clearShapes() %>%
addCircles(radius = ~amount_claims/10, weight = 1, color = "#777777",
fillColor = ~pal(amount_claims), fillOpacity = 0.7, popup = ~paste(Country.EN)
)
})
# Use a separate observer to recreate the legend as needed.
observe({
proxy <- leafletProxy("map", data = FINAL)
# Remove any existing legend, and only if the legend is
# enabled, create a new one.
proxy %>% clearControls()
if (input$legend) {
pal <- colorpal()
proxy %>% addLegend(position = "bottomright",
pal = pal, values = ~amount_claims
)
}
})
}
shinyApp(ui, server)
回答1:
Here'is a basic solution using Shiny package :
library(shiny)
library(dplyr)
library(leaflet)
# Fake data
df <- data.frame(lng = c(-5, -5, -5, -5, -15, -15, -10),
lat = c(8, 8, 8, 8, 33, 33, 20),
year = c(2018, 2018, 2018, 2017, 2017, 2017, 2016),
stringsAsFactors = FALSE)
ui <- bootstrapPage(
tags$style(type = "text/css", "html, body {width:100%;height:100%}"),
leafletOutput("map", width = "100%", height = "100%"),
absolutePanel(top = 10, right = 10,
style="z-index:500;", # legend over my map (map z = 400)
tags$h3("map"),
sliderInput("periode", "Chronology",
min(df$year),
max(df$year),
value = range(df$year),
step = 1,
sep = ""
)
)
)
server <- function(input, output, session) {
# reactive filtering data from UI
reactive_data_chrono <- reactive({
df %>%
filter(year >= input$periode[1] & year <= input$periode[2])
})
# static backround map
output$map <- renderLeaflet({
leaflet(df) %>%
addTiles() %>%
fitBounds(~min(lng), ~min(lat), ~max(lng), ~max(lat))
})
# reactive circles map
observe({
leafletProxy("map", data = reactive_data_chrono()) %>%
clearShapes() %>%
addMarkers(lng=~lng,
lat=~lat,
layerId = ~id) # Assigning df id to layerid
})
}
shinyApp(ui, server)
来源:https://stackoverflow.com/questions/51704932/time-slider-with-leaflet-r