Plot as a mesh

Convert to a quadmesh and plot in efficient vectorized form using 'grid'.

Plot mesh

mesh_plot(
  x,
  crs = NULL,
  col = NULL,
  add = FALSE,
  zlim = NULL,
  ...,
  coords = NULL,
  maxcell = 50000
)

# S3 method for BasicRaster
mesh_plot(
  x,
  crs = NULL,
  col = NULL,
  add = FALSE,
  zlim = NULL,
  ...,
  coords = NULL,
  maxcell = 50000
)

# S3 method for SpatRaster
mesh_plot(
  x,
  crs = NULL,
  col = NULL,
  add = FALSE,
  zlim = NULL,
  ...,
  coords = NULL,
  maxcell = 50000
)

# S3 method for RasterLayer
mesh_plot(
  x,
  crs = NULL,
  col = NULL,
  add = FALSE,
  zlim = NULL,
  ...,
  coords = NULL,
  maxcell = 50000
)

# S3 method for quadmesh
mesh_plot(
  x,
  crs = NULL,
  col = NULL,
  add = FALSE,
  zlim = NULL,
  ...,
  coords = NULL,
  maxcell = 50000
)

# S3 method for stars
mesh_plot(
  x,
  crs = NULL,
  col = NULL,
  add = FALSE,
  zlim = NULL,
  ...,
  coords = NULL,
  maxcell = 50000
)

# S3 method for TRI
mesh_plot(
  x,
  crs = NULL,
  col = NULL,
  add = FALSE,
  zlim = NULL,
  ...,
  coords = NULL,
  maxcell = 50000
)

# S3 method for mesh3d
mesh_plot(
  x,
  crs = NULL,
  col = NULL,
  add = FALSE,
  zlim = NULL,
  ...,
  coords = NULL,
  prefer_quad = TRUE,
  breaks = NULL
)

Arguments

x

object to convert to mesh and plot

crs

target map projection

col

colours to use, defaults to that used by graphics::image()

add

add to existing plot or start a new one

zlim

absolute range of data to use for colour scaling (if NULL the data range is used)

...

passed through to base::plot

coords

optional input raster of coordinates of each cell, see details

maxcell

default number of raster or terra cells to plot, with a default lowish-number - set to NULL to use native resolution

prefer_quad

set to TRUE by default, if but may be FALSE to assume use of triangle rather than quad primitives - this covers the case for when a mesh3d object may have quads and triangles in the same mesh

breaks

argument passed along to palr::image_pal()

Value

nothing, used for the side-effect of creating or adding to a plot

Details

The mesh may be reprojected prior to plotting using the 'crs' argument to define the target map projection in 'PROJ string' format. (There is no "reproject" function for quadmesh, this is performed directly on the x-y coordinates of the 'quadmesh' output). The 'col' argument are mapped to the input pplied object data as in 'image', and applied relative to 'zlim' if su.

If coords is supplied, it is currently assumed to be a 2-layer RasterBrick with longitude and latitude as the cell values. These are used to geographically locate the resulting mesh, and will be transformed to the crs if that is supplied. This is modelled on the approach to curvilinear grid data used in the angstroms package. There functions are used to separate the complicated grid geometry from the grid data itself. A small fudge is applied to extend the coordinates by 1 cell to avoid losing any data due to the half cell outer margin (get in touch if this causes problems!).

If 'color' is present on the object it is used. This can be overridden by using the 'col' argument, and controlled with 'zlim' and 'breaks' in the usual graphics::image() way.

Examples

##mesh_plot(worldll)
## crop otherwise out of bounds from PROJ
rr <- raster::crop(worldll, raster::extent(-179, 179, -89, 89))
mesh_plot(rr, crs = "+proj=laea +datum=WGS84")

mesh_plot(worldll, crs = "+proj=moll +datum=WGS84")

prj <- "+proj=lcc +datum=WGS84 +lon_0=0 +lat_0=-40 +lat_1=-55 +lat_2=-20"
safe_etopo <- raster::crop(etopo, raster::extent(-80, 120, -70, 90))
gcol <- grey(seq(0, 1, length = 20))
mesh_plot(safe_etopo, crs = prj, add = FALSE, col = gcol)
safe_worldll <- raster::crop(worldll, safe_etopo)
mesh_plot(safe_worldll, crs = prj, add = TRUE)