From the Census Bureau: "Primary roads are generally divided, limited-access highways within the Federal interstate highway system or under state management. These highways are distinguished by the presence of interchanges and are accessible by ramps and may include some toll highways. Secondary roads are main arteries, usually in the U.S. highway, state highway, or county highway system. These roads have one or more lanes of traffic in each direction, may or may not be divided, and usually have at-grade intersections with many other roads and driveways.
primary_secondary_roads(state, year = NULL, ...)
an sf object with columns
LINEARID
: a unique line feature identifier (source)
FULLNAME
: display name (source)
RTTYP
: describes the types of roads used (source). Possible values are:
"C": county
"I": interstate
"M": common name
"O": other
"S": state regonized
"U": U.S.
MTFCC
: 5-digit geographic code assignment (see annual assignments)
The two-digit FIPS code of the state of the county you'd like to download the roads for. Can also be state name or abbreviation (case-insensitive).
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/maps-data/data/tiger/tgrshp2020/TGRSHP2020_TechDoc.pdf
Other transportation functions:
address_ranges()
,
primary_roads()
,
rails()
,
roads()
if (FALSE) {
library(tigris)
rds <- primary_secondary_roads()
plot(rds$geometry)
}
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