R/interactive_map.R

In KDallaporta/CapstoneProject:

#' Display earthquakes on an interactive map
#'
#' @param data A NOAA dataframe as created with eq_clean_data()
#' @param annot_col The name of the column to print in annotation as character
#' @param max_rad The maximum radius of a circle as numeric
#' @param ... Additionnal parameters to pass to leaflet (see leaflet doc)
#'
#' @import leaflet
#'
#' @return An interactive map (as leaflet widget)
#' @export
#'
#' @examples
#' eq_map(head(quakes,5))
eq_map<-function(data, annot_col = "popup_text", max_rad = 8, ...){

  #Define the popup to print
  if(annot_col %in% colnames(data)){

    if(annot_col == "date"){

      popup <- paste0(
        "<b>",
        annot_col,
        ":</b> ",
        as.character(
          unlist(
            base::format(data$date, format = "%Y-%m-%d")
                   )))

    } else {

    #Either one of data columns
    popup <- paste0(
      "<b>",
      annot_col,
      ":</b> ",
      as.character(unlist(data[,annot_col])))
}
  } else {

    #Or else a default popup
    popup <- eq_create_label(data)

  }

  #Computes a radius scale
  max_radius <- max(data$EQ_PRIMARY, na.rm = TRUE)
  radius_factor <- max_rad/max_radius

  #Print on a map
  map <- leaflet::leaflet() %>%
    leaflet::addTiles() %>%
    leaflet::addCircleMarkers(lng = data$LONGITUDE, lat = data$LATITUDE,
                        radius = data$EQ_PRIMARY*radius_factor,
                        popup = popup, color = "blue", fill = "blue", ...)

  return(map)

}

#' Create a HTML label with Location, Total Death and Magnitude informations
#'
#' @param data A NOAA dataframe as created with eq_clean_data()
#'
#' @return A character vector containing every HTML label to print
#' @export
#'
#' @examples
#' eq_map(head(quakes))
eq_create_label<-function(data){

  location <- paste0(
    "<b>Location: </b>",
    data$LOCATION_NAME,
    "<br>\n"
  )

  magnitude <- paste0(
    "<b>Magnitude: </b>",
    data$EQ_PRIMARY,
    "<br>\n"
  )

  deaths <- paste0(
    "<b>Total deaths: </b>",
    data$TOTAL_DEATHS,
    "<br>\n"
  )

  return(paste0(location, magnitude, deaths))

}