How to add multiple lat longs when converting to csv to gejson format in R

Question

I have lat/longs of a particular area. How do I insert multiple lat/lons corresponding to a single area in CSV file? I am just using random numbers right now in my CSV file. I have attached a screenshot to show my CSV file. I don't want single latitude and longitude but multiple corresponding to a single area. I have to plot them later on map box

This is the code I am using to convert my csv file to geojson file

library(geojsonio)
library(rgdal)
file_to_geojson(input = "FINAL DATA ENTRY.csv",method ="web" ) 

geojson file when created gives coordinates as this. If you see red highlighted area in my geojson output file I converted from a csv file, What I want is geometry should be polygon or multipolygon and it should include 100 coordinates not single one. How do I provide those 100+ coordinates to csv file? Ill be more clear if someone is not able to understand me. Let me know. Ignore my bad English, please.

Added My csv file.

Answer 1

Try this:

Using the sf-package which allows to combine points of a group (such as a state) to MULTIPOINT or POLYGON. In your file, some states only have one point so I just can convert it to MULTIPOINT.

And then save the sf-class as geojson.

library(geojsonio)
library(sf)
library(tidyverse)

data<- data[,c("State", "lat", "lon")]

sf_data <- st_as_sf(data, coords = c("lon", "lat"))

sf_data  %>%
  group_by(State) %>%
  summarise(geometry = st_combine(geometry)) %>%
  st_cast("POLYGON") -> res_sfdata


geojson_write(res_sfdata, file = "yourpath/res_sfdata.geojson")

You'll have to remove the other columns however. Because you have different information in them on each point you want to aggregate.

EDIT: In case you want to group by more columns:

data<- data[,c("State", "PC_Name", "lat", "lon")]

sf_data <- st_as_sf(data, coords = c("lon", "lat"))

sf_data  %>%
  group_by(State, PC_Name) %>%
  summarise(geometry = st_combine(geometry)) %>%
  st_cast("POLYGON") %>%
  group_by(State) %>%
  summarise(geometry = st_combine(geometry)) 
  st_cast("MULTIPOLYGON") -> res_sfdata