Shiny: how to plot several parameters on the same leaflet map? - r

Question

I'm new to shiny. I want to make a shiny app that shows the spatial distribution of different parameters. I used meuse dataset from sp package.
Here is the code I used
library(sp)
library(rgdal)
library(ggmap)
library(leaflet)
library(dplyr)
library(shiny)
ui <- fluidPage(
mainPanel(
titlePanel("Copper (ppm)"),
leafletOutput("copper"),
titlePanel("Lead (ppm)"),
leafletOutput("lead"),
titlePanel("Zinc (ppm)"),
leafletOutput("zinc")
)
)
server <- function(input,output){
output$copper <- renderLeaflet({
data(meuse)
coordinates(meuse) <- 1:2
proj4string(meuse) <- CRS("+init=epsg:28992")
meuse <- spTransform(meuse, CRS("+proj=longlat +datum=WGS84"))
meuse_df <- as.data.frame(meuse)
leaflet(meuse_df) %>%
addProviderTiles("OpenStreetMap", group = "OpenStreetMap") %>%
addProviderTiles("Esri.WorldImagery", group = "Esri.WorldImagery") %>%
addCircleMarkers(~x,
~y,
radius = ~copper/10,
stroke = FALSE,
fillOpacity = 0.4,
group = "meuse_df",
popup = ~as.character(copper)) %>%
addLayersControl(position = "bottomleft",
baseGroups = c("OpenStreetMap",
"Esri.WorldImagery"),
overlayGroups = "meuse_df")
})
output$lead <- renderLeaflet({
leaflet(meuse_df) %>%
addProviderTiles("OpenStreetMap", group = "OpenStreetMap") %>%
addProviderTiles("Esri.WorldImagery", group = "Esri.WorldImagery") %>%
addCircleMarkers(~x,
~y,
radius = ~lead/50,
stroke = FALSE,
fillOpacity = 0.4,
group = "meuse_df",
popup = ~as.character(lead)) %>%
addLayersControl(position = "bottomleft",
baseGroups = c("OpenStreetMap",
"Esri.WorldImagery"),
overlayGroups = "meuse_df")
})
output$zinc <- renderLeaflet({
leaflet(meuse_df) %>%
addProviderTiles("OpenStreetMap", group = "OpenStreetMap") %>%
addProviderTiles("Esri.WorldImagery", group = "Esri.WorldImagery") %>%
addCircleMarkers(~x,
~y,
radius = ~zinc/100,
stroke = FALSE,
fillOpacity = 0.4,
group = "meuse_df",
popup = ~as.character(zinc)) %>%
addLayersControl(position = "bottomleft",
baseGroups = c("OpenStreetMap",
"Esri.WorldImagery"),
overlayGroups = "meuse_df")
})
}
shinyApp(ui = ui, server = server)
and here is the result I got
I wonder if there is a way to plot all parameters (copper, lead and zinc) on one map. Any suggestions would be appreciated.
UPDATE
Thanks to #Symbolix's answer and suggestion of using checkBoxGroupInput. Instead, I used addCircleMarkers three times so I can plot all the metals on one map and I can switch them on and off
ui <- fluidPage(
mainPanel(
titlePanel("All metals (ppm)"),
leafletOutput("metals")
)
)
server <- function(input,output){
output$metals <- renderLeaflet({
data(meuse)
coordinates(meuse) <- 1:2
proj4string(meuse) <- CRS("+init=epsg:28992")
meuse <- spTransform(meuse, CRS("+proj=longlat +datum=WGS84"))
meuse_df <- as.data.frame(meuse)
leaflet(meuse_df) %>%
addProviderTiles("OpenStreetMap", group = "OpenStreetMap") %>%
addProviderTiles("Esri.WorldImagery", group = "Esri.WorldImagery") %>%
addCircleMarkers(~x,
~y,
radius = ~copper/10,
color ="red",
stroke = FALSE,
fillOpacity = 0.4,
group = "copper",
popup = ~as.character(copper)) %>%
addCircleMarkers(~x,
~y,
radius = ~lead/50,
color ="gren",
stroke = FALSE,
fillOpacity = 0.4,
group = "lead",
popup = ~as.character(lead)) %>%
addCircleMarkers(~x,
~y,
radius = ~zinc/100,
color ="blue",
stroke = FALSE,
fillOpacity = 0.4,
group = "zinc",
popup = ~as.character(zinc)) %>%
addLayersControl(position = "bottomleft",
baseGroups = c("OpenStreetMap",
"Esri.WorldImagery"),
overlayGroups = c("copper",
"lead",
"zinc"))
})
}
shinyApp(ui = ui, server = server)

Answer 1

Melt your data so that your metals are in one column and you're good to go.
Here I use library(reshape2) to do the melt.
library(sp)
library(rgdal)
library(ggmap)
library(leaflet)
library(dplyr)
library(shiny)
library(reshape2)
ui <- fluidPage(
mainPanel(
titlePanel("Metals"),
leafletOutput("all_metals")
)
)
server <- function(input,output){
output$all_metals <- renderLeaflet({
data(meuse)
coordinates(meuse) <- 1:2
proj4string(meuse) <- CRS("+init=epsg:28992")
meuse <- spTransform(meuse, CRS("+proj=longlat +datum=WGS84"))
meuse_df <- as.data.frame(meuse)
## melt df so 'metals' are in one column
## using 'reshape2' library
meuse_melt <- melt(meuse_df, measure.vars = c("copper","lead","zinc"), variable.name = "metal")
## specify factor levels for colours
meuse_melt$metal <- factor(sample.int(5L, nrow(meuse_melt), TRUE))
factpal <- colorFactor(topo.colors(5), meuse_melt$metal)
## now you just need one output
leaflet(meuse_melt) %>%
addProviderTiles("OpenStreetMap", group = "OpenStreetMap") %>%
addProviderTiles("Esri.WorldImagery", group = "Esri.WorldImagery") %>%
addCircleMarkers(~x,
~y,
radius = ~value/100,
stroke = FALSE,
fillOpacity = 0.4,
group = "meuse_melt",
popup = ~metal,
color= ~factpal(metal)) %>%
addLayersControl(position = "bottomleft",
baseGroups = c("OpenStreetMap", "Esri.WorldImagery"), overlayGroups = "meuse_melt")
})
}
shinyApp(ui = ui, server = server)

Answer 2

To save you lines of code you could use mapview which provides multi-layer maps out of the box. If you only want certain attributes you can simply supply their names (or column numbers) to the 'zcol' argument. Alternatively, you can use 'burst = TRUE' to display all layers/columns present in the attribute table.
library(mapview)
library(sp)
data(meuse)
coordinates(meuse) <- ~x+y
proj4string(meuse) <- CRS("+init=epsg:28992")
mapview(meuse, zcol = c("copper", "lead", "zinc"))
## all layers
mapview(meuse, burst = TRUE)
mapview can be used with renderLeaflet.