gg.fm_mesh_2d: Geom for inla.mesh objects

Description

This function extracts the graph of an inla.mesh object and uses geom_line to visualize the graph's edges. Alternatively, if the color argument is provided, interpolates the colors across for a set of SpatialPixels covering the mesh area and calls gg.SpatialPixelsDataFrame() to plot the interpolation. Requires the ggplot2 package.

Usage

# S3 method for fm_mesh_2d
gg(
  data,
  color = NULL,
  alpha = NULL,
  edge.color = "grey",
  edge.linewidth = 0.25,
  interior = TRUE,
  int.color = "blue",
  int.linewidth = 0.5,
  exterior = TRUE,
  ext.color = "black",
  ext.linewidth = 1,
  crs = NULL,
  mask = NULL,
  nx = 500,
  ny = 500,
  ...
)
# S3 method for inla.mesh
gg(
  data,
  color = NULL,
  alpha = NULL,
  edge.color = "grey",
  edge.linewidth = 0.25,
  interior = TRUE,
  int.color = "blue",
  int.linewidth = 0.5,
  exterior = TRUE,
  ext.color = "black",
  ext.linewidth = 1,
  crs = NULL,
  mask = NULL,
  nx = 500,
  ny = 500,
  ...
)

Value

geom_line return values or, if the color argument is used, the values of gg.SpatialPixelsDataFrame().

Arguments

data: An fm_mesh_2d object.
color: A vector of scalar values to fill the mesh with colors. The length of the vector mus correspond to the number of mesh vertices. The alternative name colour is also recognised.
alpha: A vector of scalar values setting the alpha value of the colors provided.
edge.color: Color of the regular mesh edges.
edge.linewidth: Line width for the regular mesh edges. Default 0.25
interior: If TRUE, plot the interior boundaries of the mesh.
int.color: Color used to plot the interior constraint edges.
int.linewidth: Line width for the interior constraint edges. Default 0.5
exterior: If TRUE, plot the exterior boundaries of the mesh.
ext.color: Color used to plot the exterior boundary edges.
ext.linewidth: Line width for the exterior boundary edges. Default 1
crs: A CRS object supported by fm_transform() defining the coordinate system to project the mesh to before plotting.
mask: A SpatialPolygon defining the region that is plotted.
nx: Number of pixels in x direction (when plotting using the color parameter).
ny: Number of pixels in y direction (when plotting using the color parameter).
...: ignored arguments (S3 generic compatibility).

Functions

gg(inla.mesh): Alias for gg.fm_mesh_2d, supporting inla.mesh objects.

Examples

Run this code

# \donttest{
if (require(fmesher, quietly = TRUE) &&
    require(ggplot2, quietly = TRUE)) {

  # Load Gorilla data
  data("gorillas", package = "inlabru")

  # Plot mesh using default edge colors

  ggplot() +
    gg(gorillas$mesh)

  # Don't show interior and exterior boundaries

  ggplot() +
    gg(gorillas$mesh, interior = FALSE, exterior = FALSE)

  # Change the edge colors

  ggplot() +
    gg(gorillas$mesh,
      edge.color = "green",
      int.color = "black",
      ext.color = "blue"
    )

  # Use the x-coordinate of the vertices to colorize the triangles and
  # mask the plotted area by the survey boundary, i.e. only plot the inside

  xcoord <- gorillas$mesh$loc[, 1]
  ggplot() +
    gg(gorillas$mesh, color = (xcoord - 580), mask = gorillas$boundary) +
    gg(gorillas$boundary)
}
# }