library(dplyr)
library(tidyr)
library(maps)
setwd(file.path(system.file(package="FARSaccess")))
#' Load single Fatality Analysis Reporting System (FARS) file
#'
#' This function reads a specified file as a tibble format (tbl_df class). The \code{filename}
#' argument should be the path of the file to read.
#'
#' @param filename A file path where the function should look for the FARS data file. .gz, .bz2,
#' .xz, or .zip files will be automatically uncompressed. Files starting with http://, https://,
#' ftp://, or ftps:// will be automatically downloaded.
#'
#' @importFrom dplyr tbl_df
#'
#' @return tibble containing the specified FARS data. If the file is not found at the specified path
#' the function will return an error. Issues reading in the CSV file also return errors.
#'
#' @examples
#' fars_read("data.csv")
#' fars_read("accident_2013.csv.bz2")
#'
#' @export
fars_read <- function(filename) {
if(!file.exists(filename))
stop("file '", filename, "' does not exist")
data <- get(load(filename))
dplyr::tbl_df(data)
}
#' Create file name for FARS data file
#'
#' This function creates a pathname f
#' or FARS data for each specified year.
#'
#' @param year Integer or character string for the year to find data for.
#'
#'
#' @return file path for the specified annual FARS data. If the function is not able to coerce the input
#' to an integer the function will generate an error.
#'
#' @examples
#' make_filename(2015)
#' make_filename("2013")
#'
#' @export
make_filename <- function(year) {
year <- as.integer(year)
file.path(system.file("data", package="FARSaccess"), paste0("accident_",as.character(year),".rda"))
# paste0("accident_",as.character(year))
}
#' Load FARS data files
#'
#' This function loads FARS files for specified years.
#'
#' @param years Integer or character vector for the years to load data for.
#'
#' @importFrom dplyr mutate select %>%
#'
#' @return separate tibbles for each year. If the function is not able to coerce the inputs
#' to integers the function will generate an error. If the files are not found at the current working
#' directory the function will return an error. Issues reading in the CSV files also return errors.
#'
#' @examples
#' fars_read_years(c(2014,2015))
#' fars_read_years("2013")
#'
#' @export
fars_read_years <- function(years) {
lapply(years, function(year) {
file <- make_filename(year)
tryCatch({
dat <- fars_read(file)
# dplyr::mutate(dat, year = year) %>%
# dplyr::select(MONTH, year)
return(dat)
}, error = function(e) {
warning("invalid year: ", year)
return(NULL)
})
})
}
#' Load FARS data files and show counts
#'
#' This function loads FARS files for specified years and shows a count of records for each year.
#'
#' @inheritParams fars_read_years
#'
#' @importFrom dplyr bind_rows group_by summarize
#' @importFrom tidyr spread
#'
#' @return table containing data for all specified years and the count of records for each year.
#' If the function is not able to coerce the inputs to integers the function will generate an error.
#' If the files are not found at the current working directory the function will return an error.
#' Issues reading in the CSV files also return errors.
#'
#' @examples
#' fars_summarize_years(c(2014,2015))
#' fars_summarize_years("2013")
#'
#' @export
fars_summarize_years <- function(years) {
dat_list <- fars_read_years(years)
dplyr::bind_rows(dat_list) %>%
dplyr::group_by(YEAR, MONTH) %>%
dplyr::summarize(n = n()) %>%
tidyr::spread(YEAR, n)
}
#' Map FARS data reports for a state
#'
#' This function creates a map of fatal vehicle traffic crashes in a specified state and year.
#'
#' @param state.num Integer or character vector for the state FIPS number to map.
#' @param year Integer or character vector for the year to map.
#'
#' @importFrom maps map
#' @importFrom graphics points
#' @importFrom dplyr filter
#'
#' @return map plot showing latitude and longitude locations of traffic fatalities in the specified
#' state and year. If the function is not able to coerce the inputs to integers the function will
#' generate an error. If the files are not found at the current working directory the function
#' will return an error. Issues reading in the CSV files also return errors.
#'
#' @examples
#' fars_map_state(42, 2014)
#' fars_read_years(12, "2013")
#'
#' @export
fars_map_state <- function(state.num, year) {
filename <- make_filename(year)
data <- fars_read(filename)
state.num <- as.integer(state.num)
if(!(state.num %in% unique(data$STATE)))
stop("invalid STATE number: ", state.num)
data.sub <- dplyr::filter(data, STATE == state.num)
if(nrow(data.sub) == 0L) {
message("no accidents to plot")
return(invisible(NULL))
}
is.na(data.sub$LONGITUD) <- data.sub$LONGITUD > 900
is.na(data.sub$LATITUDE) <- data.sub$LATITUDE > 90
with(data.sub, {
maps::map("state", ylim = range(LATITUDE, na.rm = TRUE),
xlim = range(LONGITUD, na.rm = TRUE))
graphics::points(LONGITUD, LATITUDE, pch = 46)
})
}
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