Description from the US Census Bureau (see link for source): The primary legal divisions of most states are termed counties. In Louisiana, these divisions are known as parishes. In Alaska, which has no counties, the equivalent entities are the organized boroughs, city and boroughs, municipalities, and census areas; the latter of which are delineated cooperatively for statistical purposes by the state of Alaska and the Census Bureau. In four states (Maryland, Missouri, Nevada, and Virginia), there are one or more incorporated places that are independent of any county organization and thus constitute primary divisions of their states. These incorporated places are known as independent cities and are treated as equivalent entities for purposes of data presentation. The District of Columbia and Guam have no primary divisions, and each area is considered an equivalent entity for purposes of data presentation. All of the counties in Connecticut and Rhode Island and nine counties in Massachusetts were dissolved as functioning governmental entities; however, the Census Bureau continues to present data for these historical entities in order to provide comparable geographic units at the county level of the geographic hierarchy for these states and represents them as nonfunctioning legal entities in data products. The Census Bureau treats the following entities as equivalents of counties for purposes of data presentation: municipios in Puerto Rico, districts and islands in American Samoa, municipalities in the Commonwealth of the Northern Mariana Islands, and islands in the U.S. Virgin Islands. Each county or statistically equivalent entity is assigned a three-character numeric Federal Information Processing Series (FIPS) code based on alphabetical sequence that is unique within state and an eight-digit National Standard feature identifier.
counties(state = NULL, cb = FALSE, resolution = "500k", year = NULL, ...)The two-digit FIPS code (string) of the state you want, or a vector of codes if you want multiple states. Can also be state name or state abbreviation.
If cb is set to TRUE, download a generalized (1:500k) counties file. Defaults to FALSE (the most detailed TIGER file).
The resolution of the cartographic boundary file (if cb == TRUE). Defaults to '500k'; options include '5m' (1:5 million) and '20m' (1:20 million).
the data year; defaults to 2022
arguments to be passed to internal function load_tiger, which is not exported. See Additional Arguments.
Additional arguments that can be passed in ... are:
class Desired class of return object: "sf" (the default) or "sp". sp classes should be considered deprecated as of tigris version 2.0, but legacy support is still available.
progress_bar If set to FALSE, do not display download progress bar (helpful for R Markdown documents). Defaults to TRUE.
keep_zipped_shapefile If set to TRUE, do not delete zipped shapefile (stored in temporary directory or TIGRIS_CACHE_DIR
depending on the configuration of global option "tigris_use_cache"). Defaults to FALSE.
refresh Whether to re-download cached shapefiles (TRUE or FALSE) . The default is either FALSE or the value of global
option "tigris_refresh" if it is set. Specifying this argument will override the behavior set in "tigris_refresh" global option.
filter_by Geometry used to filter the output returned by the function. Can be an sf object, an object of class bbox, or a length-4 vector of format c(xmin, ymin, xmax, ymax) that can be converted to a bbox. Geometries that intersect the input to filter_by will be returned.
https://www2.census.gov/geo/pdfs/reference/GARM/Ch4GARM.pdf
Other general area functions:
block_groups(),
blocks(),
county_subdivisions(),
places(),
pumas(),
school_districts(),
states(),
tracts(),
zctas()
if (FALSE) {
library(tigris)
library(ggplot2)
me <- counties("Maine", cb = TRUE)
gg <- ggplot()
gg <- gg + geom_sf(data = me, color="black",
fill="white", size=0.25)
gg
}
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