mesh_plot: Plot as a mesh

In hypertidy/quadmesh: Quadrangle Mesh

Plot as a mesh

Description

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

Plot mesh

Usage

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

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

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

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

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

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

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

## S3 method for class '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()

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.

Value

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

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)

hypertidy/quadmesh documentation built on Sept. 6, 2022, 12:14 a.m.