excursions (version 2.5.8)

submesh.grid: Extract a part of a grid

Description

Extracts a part of a grid.

Usage

submesh.grid(z, grid = NULL)

Value

An inla.mesh object.

Arguments

z

A matrix with values indicating which nodes that should be present in the submesh.

grid

A list with locations and dimensions of the grid.

Author

Finn Lindgren

Examples

if (FALSE) {
if (require("fmesher")) {
  nxy <- 40
  x <- seq(from = 0, to = 4, length.out = nxy)
  lattice <- fm_lattice_2d(x = x, y = x)
  mesh <- fm_rcdt_2d_inla(lattice = lattice, extend = FALSE, refine = FALSE)

  # extract a part of the mesh inside a circle
  xy.in <- rowSums((mesh$loc[, 1:2] - 2)^2) < 1
  submesh <- submesh.grid(
    matrix(xy.in, nxy, nxy),
    list(loc = mesh$loc, dim = c(nxy, nxy))
  )
  plot(mesh$loc[, 1:2])
  lines(2 + cos(seq(0, 2 * pi, length.out = 100)), 2 + sin(seq(0, 2 * pi, length.out = 100)))
  plot(submesh, add = TRUE)
  points(mesh$loc[xy.in, 1:2], col = "2")
}
}