RcensusPkg (version 0.1.5)

tiger_water_sf: tiger_water_sf

Description

This function performs three tasks:

1. Download to an output directory a zip file from the TIGER/Line Shapefiles database.

2. Unzip the zip file and locate the shape file of interest.

3. Read and convert the shape file to a simple feature object.

Usage

tiger_water_sf(
  state = NULL,
  county = NULL,
  output_dir = tempdir(),
  delete_files = TRUE,
  vintage = 2020,
  entity = "area",
  set_crs = NULL,
  transform_crs = NULL,
  sf_info = FALSE,
  do_progress = FALSE,
  shapefile = NULL,
  datafile = NULL,
  datafile_key = NULL,
  sf_key = "GEOID",
  express = NULL,
  check_na = FALSE
)

Value

A data frame object of class sf

Arguments

state

The two-digit FIPS code for the state of interest. See usmap::fips function for finding FIPS codes.

county

The three-digit FIPS code for the county of interest.

output_dir

A full directory path where the shapefile and its associated files will be downloaded. The default is the directory defined by the value returned by tempdir().

delete_files

A logical which if TRUE will delete the shapefile and associated files in 'output_dir'`. The default is TRUE.

vintage

A numeric that sets the vintage of interest. The default is 2020. The value should be greater than 2010.

entity

A character string that sets the specific water entity of interest. The acceptable values are "area", "linear", or "coastline". The default is "area".

set_crs

A numeric or character string which if non-NULL calls sf::st_crs() to set the crs of the geometries and transforms them.

transform_crs

A numeric or character string which if non-NULL calls sf::st_transform() to perform a crs transform of the geometries. Note that the crs of the shapefile must not be NA.

sf_info

A logical which if TRUE displays info on the resulting simple feature object.

do_progress

A logical which if TRUE displays a progress bar during the download.

shapefile

A full file path to a shapefile folder with its unzipped files to be processed instead of downloading.

datafile

A dataframe containing data that should be joined with this function's resultant simple feature object.

datafile_key

The column name from 'datafile' dataframe used to key with the 'sf_key' column of the resultant simple feature dataframe.

sf_key

The column from the resultant dataframe used to key with the 'datafile' dataframe.

express

A logical expression object used to filter the resultant simple feature dataframe. For example, one of the columns of the resultant simple feature dataframe is "STATEFP". If you wanted to return just the geometries for Florida (which has a fips code of "12"), then you assign 'express' equal to: expression(STATEFP == "12"). The expression will be evaluated and only the geometries for Florida will be returned.

check_na

A logical which if TRUE will remove rows that have missing values for any of the columns. The default is to not check the columns for NA values.

Note: If entity equals "coastline" then the state and county arguments are not required.

Details

Returns simple feature (sf) water related geometric polygons provided by the US Census Bureau's TIGER/Line Shapefiles database. See Simple Features for R for more information on simple features. Along with the geometries, additional water related variables are provided. See Appendix J. Record Layouts: Hydrography (Area and Line) for a description of water related area and line variables of the sf file. See Appendix L-2. Record Layout: Coastlines Shapefile for a description of coastline related variables of the sf file. For further information on the Census Bureau's shape files see About the 2021 TIGER/Line Shapefiles. From Chapter 4.10 Hydrography (Area and Linear and 4.12.2 Coastline -- "The area hydrography shapefile contains the geometry and attributes of both perennial and intermittent area hydrography features (e.g., ponds, lakes, oceans, swamps, glaciers, and the area covered by large streams represented as double-line drainage). The linear hydrography shapefile includes streams/rivers, braided streams, canals, ditches, artificial paths, and aqueducts. A linear hydrography feature may include edges with both perennial and intermittent persistence"

The function returns the simple feature object which can easily be mapped (see RplotterPkg::create_sf_plot()) or joined with US Census Bureau demographic data via the GEOID value.

Some earlier vintages may have NA for the crs so you may need to specify the 'crs_transform' to 3426. Also you may be interested in using a state level crs. See epsg.io to search worldwide for crs.

Examples

library(sf)
library(data.table)
library(downloader)
library(usmap)
library(withr)
library(RcensusPkg)

# Get the water areas for a county in Ohio
state_county_fips <- usmap::fips(state = "Ohio", county = "Geauga")
state_fips <- substr(state_county_fips,1,2)
county_fips <- substr(state_county_fips,3,5)
# Define a temporary output folder for the downloaded shapefiles
output_dir <- withr::local_tempdir()
if(!dir.exists(output_dir)){
  dir.create(output_dir)
}
geauga_area_water_sf <- RcensusPkg::tiger_water_sf(
  state = state_fips,
  county = county_fips,
  output_dir = output_dir,
  delete_files = FALSE
)