Make a lattice object

Construct a lattice grid for fm_mesh_2d()

Usage

fm_lattice_2d(...)

# Default S3 method
fm_lattice_2d(
  x = seq(0, 1, length.out = 2),
  y = seq(0, 1, length.out = 2),
  z = NULL,
  dims = if (is.matrix(x)) {
     dim(x)
 } else {
     c(length(x), length(y))
 },
  units = NULL,
  crs = NULL,
  ...
)

Arguments

...

Passed on to submethods

x

vector or grid matrix of x-values. Vector values are sorted before use. Matrix input is assumed to be a grid of x-values with the same ordering convention of as.vector(x) as rep(x, times = dims[2]) for vector input.

y

vector of grid matrix of y-values. Vector values are sorted before use. Matrix input is assumed to be a grid of y-values with the same ordering convention of as.vector(y) as rep(y, each = dims[1]) for vector input.

z

if x is a matrix, a grid matrix of z-values, with the same ordering as x and y. If x is a vector, z is ignored.

dims

the size of the grid, length 2 vector

units

One of c("default", "longlat", "longsinlat", "mollweide") or NULL (equivalent to "default").

crs

An optional fm_crs, sf::st_crs, or sp::CRS object, denoting the CRS info for the x-y grid.

Value

An fm_lattice_2d object with elements

dims

integer vector

x

x-values for original vector input

y

y-values for original vector input

loc

matrix of (x, y) values or (x, y, z) values. May be altered by fm_transform()

segm

fm_segm object

crs

fm_crs object for loc, or NULL

crs0

fm_crs object for (x,y), or NULL

See also

fm_mesh_2d()

Other object creation and conversion: fm_as_fm(), fm_as_lattice_2d(), fm_as_mesh_1d(), fm_as_mesh_2d(), fm_as_mesh_3d(), fm_as_segm(), fm_as_sfc(), fm_as_tensor(), fm_mesh_1d(), fm_mesh_2d(), fm_segm(), fm_simplify(), fm_tensor()

Author

Finn Lindgren finn.lindgren@gmail.com

Examples

lattice <- fm_lattice_2d(
  seq(0, 1, length.out = 17),
  seq(0, 1, length.out = 10)
)

## Use the lattice "as-is", without refinement:
mesh <- fm_rcdt_2d_inla(lattice = lattice, boundary = lattice$segm)
mesh <- fm_rcdt_2d_inla(lattice = lattice, extend = FALSE)

## Refine the triangulation, with limits on triangle angles and edges:
mesh <- fm_rcdt_2d(
  lattice = lattice,
  refine = list(max.edge = 0.08),
  extend = FALSE
)

## Add an extension around the lattice, but maintain the lattice edges:
mesh <- fm_rcdt_2d(
  lattice = lattice,
  refine = list(max.edge = 0.08),
  interior = lattice$segm
)

## Only add extension:
mesh <- fm_rcdt_2d(lattice = lattice, refine = list(max.edge = 0.08))