get_ensemble_climate_data.R

#' Download ensemble climate data
#'
#' @description Download ensemble data for all models, returns the 10th, 50th and 90th
#' percentile of all models (15 for A1, 13 for B2).  Ensemble requets can be for
#' countries or basins.
#'
#' @import httr plyr reshape2 jsonlite
#' @param locator The ISO3 country code that you want data about.
#' (http://unstats.un.org/unsd/methods/m49/m49alpha.htm) or the basin ID [1-468]
#' @param geo_type basin or country depending on the locator type
#' @param type the type of data you want "mavg" for monthly averages, "annualavg"
#' @param cvar The variable you're interested in. "pr" for precipitation, "tas" for
#' temperature in celcius.
#' @param start The starting year you want data for, can be in the past or the future.
#' Must conform to the periods outlined in the world bank API.  If given values don't
#' conform to dates, the fuction will automatically round them.
#' @param end The ending year you want data for, can be in the past or the future.
#' Similar to the start date, dates will be rounded to the nearest end dat.
get_ensemble_climate_data <- function(locator, 
                                      geo_type, 
                                      type, 
                                      cvar, 
                                      start, 
                                      end){
  base_url <- "http://climatedataapi.worldbank.org/climateweb/rest/v1/"
  
  ### Error handling
  if(geo_type == "country"){
    check_ISO_code(locator)
  }

  if(geo_type == "basin"){
    if(is.na(as.numeric(locator))){
      stop("You must enter a valid Basin number between 1 and 468")
    }
    if(as.numeric(locator) < 1 || as.numeric(locator) > 468){
      as.numeric(locator) < 1 || as.numeric(locator) > 468
    }
  }

  data_url <- paste(geo_type, type, "ensemble", cvar, start, end, locator, sep="/")
  extension <- ".json"
  full_url <- paste(base_url, data_url, extension, sep="")
  raw_data <- try(content(RETRY("GET", full_url, terminate_on = c(404)), as="text"), silent=TRUE)
  data_out <- jsonlite::fromJSON(raw_data)
#   json <- jsonlite::fromJSON(raw_data, FALSE)
#   data_out <- plyr::rbind.fill(lapply(json, function(z) {
#     z <- lapply(z, function(w) {
#       if (is(w, "list")) {
#         unlist(w)
#       } else {
#         w
#       }
#     })
#     data.frame(z, stringsAsFactors = FALSE)
#   }))

  if(sum(grep("unexpected", data_out)) > 0){
    stop(paste("You entered a country for which there is no data. ",locator," is not a country with any data"))
  }
  # data_out <- ldply(parsed_data,data.frame)
  if(type == "mavg" && start < 2010){
    ### Unpack the lists
    tmp <- data.frame(sapply(data_out$monthV,unlist))
    colnames(tmp) <- data_out$percentile
    tmp$fromYear <- rep(start,12)
    tmp$toYear <- rep(end,12)
    data_out <- melt(tmp,id.vars =c("fromYear","toYear"), variable.name = "percentile", value.name = "data")
    data_out$month  <- rep(1:12,dim(data_out)[1]/12)
  }

  if (type == "mavg" && start > 2010) {
    do_list <- list()
    for(i in 1:length(unique(data_out$scenario))) {
      ### Unpack the lists
      split_do <- subset(data_out,data_out$scenario == unique(data_out$scenario)[i])
      tmp <- data.frame(sapply(split_do$monthV,unlist))
      colnames(tmp) <- split_do$percentile
      tmp$fromYear <- rep(start,12)
      tmp$toYear <- rep(end,12)
      do_list[[i]] <- melt(tmp,id.vars =c("fromYear", "toYear"), variable.name = c("percentile"), value.name = "data")
      do_list[[i]]$scenario <- rep(split_do$scenario[1], dim(do_list[[i]])[1])
      do_list[[i]]$month  <- rep(1:12, dim(do_list[[i]])[1]/12)
    }
    data_out <- do.call(rbind, do_list)
  }

  if (start < 2010) {
    tmp_names <- c("scenario", colnames(data_out))
    data_out <- cbind(rep("past", dim(data_out)[1]), data_out)
    colnames(data_out) <- tmp_names
  }

  data_out$locator <- rep(locator, dim(data_out)[1])
  data_out <- fix_emblist(data_out)

  return(data_out)
}

fix_emblist <- function(vv) {
  types <- vapply(vv, class, "")
  for (i in seq_along(types)) {
    if (types[[i]] == "list") {
      vv[,i] <- unlist(vv[,i])
    }
  }
  vv
}