Coordinate reference system for spatial computations

crs_eqc() gives a CRS that can be used for e.g. computing centroids or distances. It is an equidistant cylindrical system that by does not distort latitudes near latitude. The CRS is in units of kilometres by default.

Usage

crs_eqc(latitude = 0, units = "km")

Arguments

latitude: The latitude of true scale (the proj parameter lat_ts). This is the latitude where the scale is not distorted by the projection.
units: Base length unit (e.g. "km" or "mi"). See ggmapinset::configure_inset() for supported values.

Value

CRS object from sf.

Examples

# Sydney, Australia has a latitude of 33.87 S so this CRS will be suitable
# for computations close to there:
crs_eqc(latitude = -33.87)
#> Coordinate Reference System:
#>   User input: +proj=eqc +lat_ts=-33.87 +units=km 
#>   wkt:
#> PROJCRS["unknown",
#>     BASEGEOGCRS["unknown",
#>         DATUM["World Geodetic System 1984",
#>             ELLIPSOID["WGS 84",6378137,298.257223563,
#>                 LENGTHUNIT["metre",1]],
#>             ID["EPSG",6326]],
#>         PRIMEM["Greenwich",0,
#>             ANGLEUNIT["degree",0.0174532925199433],
#>             ID["EPSG",8901]]],
#>     CONVERSION["unknown",
#>         METHOD["Equidistant Cylindrical",
#>             ID["EPSG",1028]],
#>         PARAMETER["Latitude of 1st standard parallel",-33.87,
#>             ANGLEUNIT["degree",0.0174532925199433],
#>             ID["EPSG",8823]],
#>         PARAMETER["Longitude of natural origin",0,
#>             ANGLEUNIT["degree",0.0174532925199433],
#>             ID["EPSG",8802]],
#>         PARAMETER["False easting",0,
#>             LENGTHUNIT["kilometre",1000],
#>             ID["EPSG",8806]],
#>         PARAMETER["False northing",0,
#>             LENGTHUNIT["kilometre",1000],
#>             ID["EPSG",8807]]],
#>     CS[Cartesian,2],
#>         AXIS["(E)",east,
#>             ORDER[1],
#>             LENGTHUNIT["kilometre",1000,
#>                 ID["EPSG",9036]]],
#>         AXIS["(N)",north,
#>             ORDER[2],
#>             LENGTHUNIT["kilometre",1000,
#>                 ID["EPSG",9036]]]]