Unable to generate maps using leaflet

[Kris22]

Hi all,

I have been trying to generate a map using leaflet to locate sites based on longitude and latitude column values in my csv file.

Preformatted textlibrary(tidyverse)
library(leaflet)
library(stringr)
library(sp)
library(maps)

data2 <- read.csv('siteinfo.csv')
names(data2)
mapSites = map("data2$location ", fill = TRUE, plot = FALSE)
leaflet(data = mapSites) %>% addTiles() %>%
addMarkers(~long, ~lat)Preformatted text

This is what I'm trying with.
Here is how my data frame looks

location longitude latitide
loc1 24.600 67.524
loc1 24.600 67.535
loc2 28.478 -17.789
loc3 30.654 12.397
loc3 30.654 12.397
loc3 30.654 12.397

How can I create a map? Thanks in Advance..

[jlacko]

I suggest you use the {sf} package format for your data. It will make a lot of things easier.

In my example I am first transforming your data from a regular data frame to a spatial data frame as per the {sf} package.

The {leaflet} package plays nicely with {sf}, and when you provide your data in sf format it will take care of the rest.

library(dplyr)
library(sf)
library(leaflet)

# your data:
data <- tibble::tribble(~location, ~longitude, ~latitude,
                        "loc1", 24.600, 67.524,
                        "loc1", 24.600, 67.535,
                        "loc2", 28.478, -17.789,
                        "loc3", 30.654, 12.397,
                        "loc3", 30.654, 12.397,
                        "loc3", 30.654, 12.397)

# make data feel spatial = tranform to sf format
data <- data %>% 
  st_as_sf(coords = c("longitude", "latitude"), 
           crs = 4326)

# call leaflet with your data as data object
leaflet(data = data) %>% 
  addProviderTiles("CartoDB.Positron") %>%  # a basemeap
  addMarkers(popup = ~location) # addCircleMarkers is another possibility

As a shameless plug: a while back I wrote a long form blog post about using leaflet.js in R, you might find it interesting: Leaflet in R · Jindra Lacko

[Kris22]

Hi jlacko,
But my concern is that I have all the location information in a csv file and there are so many. How can I make the R file itself extract all the location details? Any advice...

[jlacko]

And is there a problem with reading the csv in? I mean, does this not work for you?

library(dplyr)
library(sf)
library(leaflet)

data <- readr::read_csv("siteinfo.csv") %>% 
  st_as_sf(coords = c("longitude", "latitude"), 
           crs = 4326)

leaflet(data = data) %>% 
  addProviderTiles("CartoDB.Positron") %>%  # a basemeap
  addMarkers(popup = ~location) # addCircleMarkers is another possibility

[Kris22]

@jlacko

library(dplyr) library(sf) library(leaflet) data <- readr::read_csv("siteinfo.csv") %>% st_as_sf(coords = c("longitude", "latitude"), crs = 4326) leaflet(data = data) %>% addProviderTiles("CartoDB.Positron") %>% # a basemeap addMarkers(popup = ~location) # addCircleMarkers is another possibility

Nope, It is telling that cannot find function like st_as_sf

[Kris22]

library(tidyverse)
library(leaflet)
library(stringr)
library(sp)
library(maps)

data <- read.csv('siteinfo.csv')
names(data2)
mapSites <- Map("data$location", fill = TRUE, plot = FALSE)
leaflet(data = mapSites) %>% addTiles() %>%
addMarkers(~long, ~lat)

I'm trying this but it is giving error output data$location of function mode is not found.
@jlacko

[jlacko]

I suggest you install the sf package (= install.packages("sf")) - that will make the error of "cannot find function like st_as_sf" go away - and use the code I proposed. It works.

[Kris22]

Nope. It's still the same.

[nirgrahamuk]

you are simply not running the code the jlacko provided for you.
you still are using this Map() function... jlacko doesnt use that in his working code example