R/map_bgs.R

In dKvale/mnrisks2011: MNRISKS

#' map_bgs
#'
#' Map the average block group mnrisks results with leaflet
#' @param data The dataframe or sf object containing the modeling results for mapping.
#' @param result_col Column name containing the modeling concentration/risk results.
#' @param geoid_col Block group GEOID colulmn name for mapping results.
#' @param colors Color palette to use for block group fill, ex. "viridis", "inferno", "Blues", "Greens"
#' @param reverse_colors Flip the color palette order
#' @param signif_digits Number of significant figures to show in map labels.
#' @keywords Map average blockgroup mnrisks leaflet
#' @export
#' @examples
#' # For all block groups
#' map_bgs(data = mnrisk_results,
#'         result_col = "avg_cancer_risk", 
#'         colors = "Blues")
# 

map_bgs <- function(data        = NULL,
                    result_col  = "avg_risk",
                    geoid_col   = "geoid",
                    colors      = "viridis",
                    reverse_colors = T,
                    signif_digits  = 3) {
  
  if (is.null(data) | !"data.frame" %in% class(data)) stop("Incorrect data passed to function. Set `data` argument to the 'data.frame' or 'sf' object containing the modeling results.")
  
  if (!result_col %in% names(data)) stop(paste("The result_col [", result_col, "] was not found in the data."))
  
  if (!geoid_col %in% names(data)) stop(paste("The geoid_col [", geoid_col, "] was not found in the data."))
  
  
  max_result <- max(data[, result_col], na.rm = T)
  
  names(data)[grep(result_col, names(data))] <- "avg_result"
  
  names(data) <- tolower(names(data))
  
  pal <- colorNumeric(palette = colors, domain = data$avg_result, reverse = reverse_colors)
  #pal <- leaflet::colorNumeric("viridis", quantile(data$avg_result, c(seq(0,0.9,0.1),0.95,0.97,1)), reverse = T)
  
  
  if (!'sf' %in% class(data)) {
    
    bgs <- get_bg_shapes()
    
    names(bgs) <- tolower(names(bgs))
    
    bgs <- dplyr::left_join(bgs, data, by = c("geoid" = tolower(geoid_col)))
    
  } else {
    
    bgs <- data
    
  }
  
  
  bgs$label <- paste0("<h2>", 
                      result_col, 
                      "</h2><h1 style='text-align: center; color: grey;'>", 
                      signif(bgs$avg_result, signif_digits), "</h1>")


  leaflet(bgs %>% subset(!is.na(avg_result))) %>%
    addProviderTiles(providers$CartoDB.Positron) %>%
    addPolygons(fillColor  = ~pal(avg_result),
                color = ~pal(avg_result),
                fillOpacity = ~0.45*avg_result/max_result + 0.35, # Scale the opacity up to 0.8 for highest risks
                weight  = 1, 
                stroke = T,
                smoothFactor = 0.5,
                opacity = ~0.4*avg_result/max_result + 0.3, # Scale the border opacity up to 0.7 for highest risks
                label = ~lapply(label, htmltools::HTML),
                popup = ~lapply(label, htmltools::HTML)) %>%
    addLegend("bottomright", 
              pal = pal, 
              values = ~avg_result,
              title = result_col,
              opacity = 0.7)

}