Adding markers in a leaflet map made from spatial polygons dataframe

Question

I want to put markers based on lat long (I already have this data in a data frame), on a map made from spatial polygon file. I'm able to do this on a openstreetMap with the help of addTiles function but got stuck for spatial polygon file. Below is the code for with openstreet map as background

    datm <- read.csv("lat_data2.csv", header = TRUE)
#This reads the lat long data file

sample data from this file:

brand      city         lon        lat
Tata Motors ADILABAD    78.5320107  19.6640624
Maruti  Adoni   77.2728368  15.6322227
Honda   Agra    78.5080745  27.1766701
Hyundai Agra    78.0080745  26.6766701

I then plot it using

leaflet(data = datm)%>%
  addProviderTiles("Esri.WorldGrayCanvas", options = tileOptions(minZoom=5, maxZoom=7))%>%
  addMiniMap(position = "bottomright")%>%
  addMarkers(datm, lng = ~lon, lat = ~lat,label = ~datm$city,icon = ~caricon)
 #caricon is a list of png icon that i have made

which gives me this Now I only want to see map of India so is there a way to make rest of countries go blank.

To achive this what I'm trying is to do this same exercise of plotting markers on a shapefile of India, is there a alternative way of doing this ?

When I use this code

leaflet()%>%
    addPolygons(data = s)%>%
    addMarkers(lng = 73.229354, lat = 25.761765,popup = "single marker")
    # here s is a spatialolygondataframe of country india.

I get this

But I don't understand how can I give as input multiple lat long to make markers. I tried this

      leaflet()%>%

    addMarkers(lng = datm$lon, lat = datm$lat,popup = datm$city)%>%
  addPolygons(data = s) 

but this gives me error. any help is appreciated I'm stuck at this for quite a while and it's frustrating. I searched for any similar topics but couldn't find anything to solve my problem.

Answer 1

Using your example (called df here) and a shapefile called india, read like india <- readOGR('INDIA.shp') your code should be:

leaflet(data = df) %>%
  addProviderTiles("Esri.WorldGrayCanvas", options = tileOptions(minZoom=5, maxZoom=7))%>%
  addMiniMap(position = "bottomright")%>%
  addMarkers(df, lng = ~lon, lat = ~lat,label = ~df$city) %>%
  addPolygons(data = india)

As you can see, multiple markers appear on the map.

The problem that you encounter stems from not correctly writing the syntax for addMarkers, ~ needs to be stated in lat and lng arguments.