I have a leaflet map in an R shiny app and the map will not center and refocus on the selected location. Whats frustrating is this works with census data centroids but doesn't with my data.
I have the code below which works if i use some dummy data from census but when i use my own data (available on Github) it wont work. I am suspecting something with my data but i can't seem to understand what it might be.
#Load libraries
##########################################
library(shiny)
library(shinyWidgets)
library(tigris)
library(leaflet)
library(rgeos)
library(rgdal)
#Get data from here - https://github.com/JoshRoll/ODOT-Projects/blob/master/Bend_Spatial_Data_2018.gdb.zip
#Count Location spatial information
##############
#Define the location where you unzipped the downloaded file
fgdb <- "Bend_Spatial_Data_2018.gdb"
# Read the feature class
Count_Location_Info_Sp <- readOGR(dsn=fgdb,layer= "MMCountLocations")
# Load data- Use census to use as proper spatial transformation from x/y to lat/long (Uses tigris package)
States_Sp <- states( year = "2010")
#Reproject
Count_Location_Info_Sp <- spTransform(Count_Location_Info_Sp, CRS(proj4string( States_Sp)))
#Create a data frame from spatial data
Data.. <- Count_Location_Info_Sp@data
#Set up User Interface
######################
ui <- fluidPage(
titlePanel("LOcation Selector Test"),
tabsetPanel(
#Daily Counts Panel
##############
#Hourly Counts Panel
#######################
tabPanel("Tab 1",
#Call plot
fluidRow(
column(3,
uiOutput("Location_Selector"))),
#Location Details
fluidRow(
column(6,
#h4("Selected Location"),
leafletOutput("map_plot",height = 500))
#Close row
)
#Close panel
)
#Close setPanel
)
#Page end
)
#Set up Server
#---------------------------
server <- shinyServer(function(session,input,output){
#Location selector
observe({
output$Location_Selector <- renderUI({
selectInput(inputId = "Location_Selector",
label = "Select Location", multiple = FALSE,
choices = as.character(unique(Data..$Sub_Location_Id)),
selected = unique(Data..$Sub_Location_Id)[1])
})
})
#Set up starting leaflet
###############
output$map_plot <- renderLeaflet({
leaflet(Count_Location_Info_Sp) %>%
addTiles() %>%
addCircles(color = "black" )
})
#Set up proxy leaflet for updated selector
####################
observe({
dat <- Count_Location_Info_Sp[Count_Location_Info_Sp@data$Sub_Location_Id%in%input$Location_Selector,]
lat <- coordinates( dat)[,1]
long <- coordinates(dat)[,2]
leafletProxy("map_plot") %>%
clearShapes() %>%
addTiles() %>%
addCircles(data =dat ,color = "black" ) %>%
setView(lng = long, lat = lat, zoom = 14)
#Close leaflet proxy observe
})
})
#Run App
shinyApp(ui,server)
The Simple features (sf
) package is a lot easier to work with (in my opinion) and is way more feature-rich than using sp
. Here is how I would do it,
All i did was change how the data is read in using the sf package. We transform it to standatd coordinates reference frame (crs
). The dataset is using a different coordinate reference frame.
And then finally, in sf
you dont need to index into @data
. You can treat you dataframe Count_Location_Info_Sp
as a regular old dataframe (albeit with a few additional features).
#Load libraries
##########################################
library(shiny)
library(shinyWidgets)
library(tigris)
library(leaflet)
library(rgeos)
library(geosphere)
library(sf)
#Get data from here - https://github.com/JoshRoll/ODOT-Projects/blob/master/Bend_Spatial_Data_2018.gdb.zip
#Count Location spatial information
##############
#Define the location where you unzipped the downloaded file
fgdb <- "~/Downloads/Bend_Spatial_Data_2018.gdb"
# Read the feature class
Count_Location_Info_Sp <- st_read(dsn=fgdb,layer= "MMCountLocations",stringsAsFactors = FALSE)
Count_Location_Info_Sp <- st_transform(Count_Location_Info_Sp, crs = "+proj=longlat +datum=WGS84")
#Set up User Interface
######################
ui <- fluidPage(
titlePanel("LOcation Selector Test"),
tabsetPanel(
#Daily Counts Panel
##############
#Hourly Counts Panel
#######################
tabPanel("Tab 1",
#Call plot
fluidRow(
column(3,
uiOutput("Location_Selector"))),
#Location Details
fluidRow(
column(6,
#h4("Selected Location"),
leafletOutput("map_plot",height = 500))
#Close row
)
#Close panel
)
#Close setPanel
)
#Page end
)
#Set up Server
#---------------------------
server <- shinyServer(function(session,input,output){
#Location selector
observe({
output$Location_Selector <- renderUI({
selectInput(inputId = "Location_Selector",
label = "Select Location", multiple = FALSE,
choices = as.character(unique(Data..$Sub_Location_Id)),
selected = unique(Data..$Sub_Location_Id)[1])
})
})
#Set up starting leaflet
###############
output$map_plot <- renderLeaflet({
leaflet(Count_Location_Info_Sp) %>%
addTiles() %>%
addCircles(color = "black" )
})
#Set up proxy leaflet for updated selector
####################
observe({
req(input$Location_Selector)
dat <- Count_Location_Info_Sp[Count_Location_Info_Sp$Sub_Location_Id %in% input$Location_Selector,]
lat <- st_coordinates(dat)[[2]]
long <- st_coordinates(dat)[[1]]
leafletProxy("map_plot") %>%
clearShapes() %>%
addTiles() %>%
addCircles(data =dat ,color = "black" ) %>%
setView(lng = long, lat = lat, zoom = 14)
#Close leaflet proxy observe
})
})
#Run App
shinyApp(ui,server)