local_weather_data.R

#For the creation of the .Renviron file
# install.packages("usethis")  # once
# usethis::edit_r_environ()    # opens/creates your user .Renviron

key <- Sys.getenv("OPENWEATHER_API_KEY")
key
# should print your key (not empty)

install.packages("jsonlite")  # once
library(jsonlite)

city <- "Belmopan,bz"  # name,country-code
url  <- paste0(
  "https://api.openweathermap.org/data/2.5/weather",
  "?q=", city,
  "&units=imperial",
  "&appid=", key
)

j <- fromJSON(url)   # open the box (JSON → R list)

# make a tiny table
one_row <- data.frame(
  city = j$name,
  temp = j$main$temp,
  lon  = j$coord$lon,
  lat  = j$coord$lat
)

one_row


#Many cities (baby loop)

cities <- c("Belmopan,bz", "Belize City,bz", "San Ignacio,bz")

all_weather <- data.frame()

for (c in cities) {
  u <- paste0("https://api.openweathermap.org/data/2.5/weather",
              "?q=", c, "&units=metric&appid=", key)
  jj <- fromJSON(u)
  row <- data.frame(
    city = jj$name,
    temp = jj$main$temp,
    lon  = jj$coord$lon,
    lat  = jj$coord$lat
  )
  all_weather <- rbind(all_weather, row)   # add the row
}

all_weather

all_weather$hot <- all_weather$temp >= 30   # TRUE if temp ≥ 30
all_weather

#Simplest plot(bar chart)
barplot(
  all_weather$temp,
  names.arg = all_weather$city,
  ylab = "°C",
  main = "Current Temperature"
)

#Print png
png("weather_plot.png", width=800, height=600)
barplot(
  all_weather$temp,
  names.arg = all_weather$city,
  ylab = "°C",
  main = "Current Temperature"
)
dev.off()

#Simplest map
install.packages("leaflet")  # once
library(leaflet)

leaflet(all_weather) |>
  addTiles() |>
  addCircleMarkers(
    lng = ~lon, lat = ~lat,
    color = ifelse(all_weather$hot, "red", "blue"),
    radius = 6,
    label = ~paste(city, "—", temp, "°C")
  )

#create csv

dir.create("data", showWarnings = FALSE)
write.csv(all_weather, "data/weather_now.csv", row.names = FALSE)