Obtain an sf::crs or fm_crs object from a spatial object, or
convert crs information to construct a new sf::crs object.
fm_crs(x, ..., units = NULL, oblique = NULL)fm_crs_oblique(x)
# S3 method for fm_crs
st_crs(x, ...)
# S3 method for fm_crs
$(x, name)
# S3 method for default
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for crs
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for fm_crs
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for fm_CRS
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for character
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for Spatial
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for SpatVector
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for SpatRaster
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for sf
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for sfc
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for sfg
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for fm_mesh_2d
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for fm_mesh_1d
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for fm_mesh_3d
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for fm_tensor
fm_crs(x, ..., units = NULL, oblique = NULL, .multi = FALSE)
# S3 method for fm_collect
fm_crs(x, ..., units = NULL, oblique = NULL, .multi = FALSE)
# S3 method for fm_lattice_2d
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for fm_segm
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for fm_list
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for matrix
fm_crs(x, ..., units = NULL, oblique = NULL)
# S3 method for fm_list
fm_CRS(x, ..., units = NULL, oblique = NULL)
fm_wkt_predef()
# S3 method for inla.CRS
fm_crs(x, ..., units = NULL, oblique = NULL)
Either an sf::crs object or an fm_crs object,
depending on if the coordinate reference system described by the parameters
can be expressed with a pure crs object or not.
A crs object (sf::st_crs()) or a fm_crs object.
An S3 fm_crs object is a list with elements crs and oblique.
fm_wkt_predef returns a WKT2 string defining a projection
Object to convert to crs or to extract crs information from.
If character, a string suitable for sf::st_crs(x), or the name of a
predefined wkt string from ``names(fm_wkt_predef())`.
Additional parameters. Not currently in use.
character; if non-NULL, fm_length_unit()<- is called to change
the length units of the crs object. If NULL (default), the length units
are not changed. (From version 0.3.0.9013)
Numeric vector of length at most 4 of rotation angles (in
degrees) for an oblique projection, all values defaulting to zero. The
values indicate (longitude, latitude, orientation, orbit), as explained in
the Details section below. When oblique is non-NULL, used to override the
obliqueness parameters of a fm_crs object. When NA, remove obliqueness
from the object, resulting in a return class of sf::st_crs(). When
NULL, pass though any oblique information in the object, returning an
fm_crs() object if needed.
element name
logical; If TRUE, return a list of fm_crs objects
for classes that support multiple spaces. Default FALSE
fm_crs(fm_tensor): By default returns the crs of the first space in the
tensor product space.
fm_crs(fm_collect): By default returns the crs of the first space in the
collection.
fm_crs(fm_list): returns a list of 'crs' objects, one for each list element
st_crs(fm_crs): st_crs(x, ...) is equivalent to
fm_crs(x, oblique = NA, ...)
when x is a fm_crs object.
$: For a fm_crs object x, x$name calls the accessor
method for the crs object inside it. If name is "crs", the internal crs
object itself is returned. If name is "oblique", the internal oblique
angle parameter vector is returned.
fm_crs_oblique(): Return NA for object with no oblique information,
and otherwise a length 4 numeric vector.
fm_CRS(fm_list): returns a list of 'CRS' objects, one for each list element
Finn Lindgren Finn.Lindgren@gmail.com
The first two
elements of the oblique vector are the (longitude, latitude)
coordinates for the oblique centre point. The third value (orientation) is a
counter-clockwise rotation angle for an observer looking at the centre point
from outside the sphere. The fourth value is the quasi-longitude (orbit
angle) for a rotation along the oblique observers equator.
Simple oblique: oblique=c(0, 45)
Polar: oblique=c(0, 90)
Quasi-transversal: oblique=c(0, 0, 90)
Satellite orbit viewpoint: oblique=c(lon0-time*v1, 0, orbitangle, orbit0+time*v2), where lon0 is the longitude at which a satellite
orbit crosses the equator at time=0, when the satellite is at an
angle orbit0 further along in its orbit. The orbital angle relative
to the equatorial plane is orbitangle, and v1 and v2
are the angular velocities of the planet and the satellite, respectively.
Note that "forward" from the satellite's point of view is "to the right" in
the projection.
When oblique[2] or oblique[3] are non-zero, the resulting
projection is only correct for perfect spheres.
crs1 <- fm_crs("longlat_globe")
crs2 <- fm_crs("lambert_globe")
crs3 <- fm_crs("mollweide_norm")
crs4 <- fm_crs("hammer_globe")
crs5 <- fm_crs("sphere")
crs6 <- fm_crs("globe")
names(fm_wkt_predef())
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