R/import_noaa_normals.R

In vanarchist/vanlife-spot-finder: This package includes the Vanlife Spot Finder shiny app and supporting utiliities.

# Import NOAA US Climate Normals 1981-2010

# Data sources
# https://www1.ncdc.noaa.gov/pub/data/normals/1981-2010/products/temperature/
# mly-tmin-normal.txt
# https://www1.ncdc.noaa.gov/pub/data/normals/1981-2010/products/temperature/
# mly-tmax-normal.txt
# https://www1.ncdc.noaa.gov/pub/data/normals/1981-2010/products/precipitation/
# mly-prcp-normal.txt
# https://www1.ncdc.noaa.gov/pub/data/normals/1981-2010/station-inventories/
# allstations.txt

library(rprojroot)
library(dplyr)

# Read data from NOAA normals file into dataframe
read_noaa_normals_file <- function(file){
  file_path <- paste0(rprojroot::find_root("DESCRIPTION"), "/",
                      "inst/vanlife-spot-finder/data/", file)
  data <- read.table(file_path, header = FALSE, stringsAsFactors = FALSE,
                     strip.white = TRUE, fill = TRUE,
                     col.names=c("id", "jan", "feb", "mar", "apr", "may",
                                 "jun", "jul", "aug", "sep", "oct", "nov",
                                 "dec"))
  data
}

# Read data from NOAA stations file into dataframe
read_noaa_stations_file <- function(file){
  file_path <- paste0(rprojroot::find_root("DESCRIPTION"), "/",
                      "inst/vanlife-spot-finder/data/", file)
  data <- read.fwf(file_path, widths = c(11, 9, 10, 7, 3, 32, 4, 4, 6),
                   header = FALSE, stringsAsFactors = FALSE, fill = TRUE,
                   strip.white = TRUE,
                   col.names=c("id", "latitude", "longitude", "elevation",
                               "state", "name", "gsnflag", "hcnflag", "wmoid",
                               "method"))
  data
}

# Process stations file
# Data format specified in:
# https://www1.ncdc.noaa.gov/pub/data/normals/1981-2010/readme.txt
process_noaa_temp_normals_data <- function(data){
  # convert data format for all months
  data[,2:13] <- lapply(data[,2:13], strip_flag_convert_to_deg)
  data
}

# Process temperature normals data to get in usable format
# Data format specified in:
# https://www1.ncdc.noaa.gov/pub/data/normals/1981-2010/readme.txt
process_noaa_temp_normals_data <- function(data){
  # convert data format for all months
  data[,2:13] <- lapply(data[,2:13], strip_flag_convert_to_deg)
  data
}

# strip flag (ignore) and convert to degrees
strip_flag_convert_to_deg <- function(data){
  as.double(substr(data, 1, nchar(data) - 1))/10
}

# strip flag (ignore) and convert to inches
strip_flag_convert_to_in <- function(data){
  as.double(substr(data, 1, nchar(data) - 1))/100
}

# Process precipitation normals data to get in usable format
# Data format specified in:
# https://www1.ncdc.noaa.gov/pub/data/normals/1981-2010/readme.txt
process_noaa_prec_normals_data <- function(data){
  # convert data format for all months
  data[,2:13] <- lapply(data[,2:13], strip_flag_convert_to_in)
  data
}

# get max temp normals combined with station information
get_combined_data_max <- function(){
  stations <- read_noaa_stations_file("allstations.txt")
  tmax <- read_noaa_normals_file("mly-tmax-normal.txt")
  tmax <- process_noaa_temp_normals_data(tmax)
  tmax_combined <- left_join(tmax, stations, by = c("id"="id"))
}

# get min temp normals combined with station information
get_combined_data_min <- function(){
  stations <- read_noaa_stations_file("allstations.txt")
  tmin <- read_noaa_normals_file("mly-tmin-normal.txt")
  tmin <- process_noaa_temp_normals_data(tmin)
  tmin_combined <- left_join(tmin, stations, by = c("id"="id"))
}

# get precipitation temp normals combined with station information
get_combined_data_prec <- function(){
  stations <- read_noaa_stations_file("allstations.txt")
  prec <- read_noaa_normals_file("mly-prcp-normal.txt")
  prec <- process_noaa_prec_normals_data(prec)
  prec_combined <- left_join(prec, stations, by = c("id"="id"))
}