You might be looking for the usmap package: CRAN | Github | Website
usmapdata is a container package for the map data frame
used in the usmap package.
This data has been extracted to keep usmap small and easier
to maintain, while allowing the ability to keep the US map data frame
updated as often as possible (independently of usmap
updates).
This package and repository will only contain functions and data
relevant to the actual map data frame used to draw the map in the
usmap package. All other functions, including FIPS and
mapping convenience functions, will be contained in the
usmap repository.
The shape files that we use to plot the maps in R are located in the
data-raw folder. For more information refer to the US
Census Bureau. Maps at both the state and county levels are included
for convenience (zip code maps may be included in the future).
The Cartographic
Boundary Files are used for mapping in usmap,
specifically the 1:20m scale files. This low resolution allows for small
file sizes while still allowing enough detail for simple choropleths.
The file description can be read here.
data-raw
folder:
county-fips.csv
cb_2017_us_county_20m)
create-map-df.R
format-map-df.R
inst/extdata:
us_counties_centroids.csv
us_counties.csv
us_states_centroids.csv
us_states.csv
county_fips.csv (if changed)
This package should only be installed if you intend to manipulate the
US mapping data frame, which contains coordinates to draw the US state
and county boundaries. If you’re interested in plotting data on a US
map, use the usmap package.
To install from CRAN (recommended), run the following code in an R console:
install.packages("usmapdata")To install the package from this repository, run the following code in an R console:
# install.package("devtools")
devtools::install_github("pdil/usmapdata")Installing using devtools::install_github will provide
the most recent developer build of usmapdata.
⚠️ The developer build may be unstable and not function correctly, use with caution.
To begin using usmapdata, import the package using the
library command:
library(usmapdata)usmap uses an Albers equal-area
conic projection, with arguments as follows:
usmap::usmap_crs()
#> Coordinate Reference System:
#> Deprecated Proj.4 representation:
#> +proj=laea +lat_0=45 +lon_0=-100 +x_0=0 +y_0=0 +ellps=sphere
#> +units=m +no_defs
#> WKT2 2019 representation:
#> PROJCRS["unknown",
#> BASEGEOGCRS["unknown",
#> DATUM["unknown",
#> ELLIPSOID["Normal Sphere (r=6370997)",6370997,0,
#> LENGTHUNIT["metre",1,
#> ID["EPSG",9001]]]],
#> PRIMEM["Greenwich",0,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8901]]],
#> CONVERSION["unknown",
#> METHOD["Lambert Azimuthal Equal Area (Spherical)",
#> ID["EPSG",1027]],
#> PARAMETER["Latitude of natural origin",45,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8801]],
#> PARAMETER["Longitude of natural origin",-100,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8802]],
#> PARAMETER["False easting",0,
#> LENGTHUNIT["metre",1],
#> ID["EPSG",8806]],
#> PARAMETER["False northing",0,
#> LENGTHUNIT["metre",1],
#> ID["EPSG",8807]]],
#> CS[Cartesian,2],
#> AXIS["(E)",east,
#> ORDER[1],
#> LENGTHUNIT["metre",1,
#> ID["EPSG",9001]]],
#> AXIS["(N)",north,
#> ORDER[2],
#> LENGTHUNIT["metre",1,
#> ID["EPSG",9001]]]]
```
</details>
This is the same projection used by the [US National Atlas](https://epsg.io/2163).
To obtain the projection used by `usmap`, use `usmap_crs()`.
Alternatively, the CRS ([coordinate reference system](https://www.nceas.ucsb.edu/sites/default/files/2020-04/OverviewCoordinateReferenceSystems.pdf)) can be created manually with the following command:
```r
sp::CRS(paste("+proj=laea +lat_0=45 +lon_0=-100 +x_0=0 +y_0=0",
"+a=6370997 +b=6370997 +units=m +no_defs"))The code used to generate the map files was based on this blog post
by Bob Rudis:
Moving
The Earth (well, Alaska & Hawaii) With R