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View raster objects interactively without background map but in any CRS

plainView.Rd

this function produces an interactive view of the specified raster object(s) on a plain grey background but for any CRS.

Usage

# S4 method for RasterLayer
plainView(
  x,
  maxpixels = 1e+08,
  col.regions = viridisLite::inferno,
  at,
  na.color = "#BEBEBE",
  legend = TRUE,
  verbose = FALSE,
  layer.name = deparse(substitute(x, env = parent.frame())),
  gdal = TRUE,
  ...
)

# S4 method for RasterStackBrick
plainView(
  x,
  r = 3,
  g = 2,
  b = 1,
  na.color = "#BEBEBE",
  maxpixels = 1e+08,
  layer.name = deparse(substitute(x, env = parent.frame())),
  ...
)

# S4 method for SpatialPixelsDataFrame
plainView(x, zcol = 1, ...)

# S4 method for ANY
plainview(...)

Arguments

x

a raster* object

maxpixels

integer > 0. Maximum number of cells to use for the plot. If maxpixels < ncell(x), sampleRegular is used before plotting.

col.regions

color (palette).See levelplot for details.

at

the breakpoints used for the visualisation. See levelplot for details.

na.color

color for missing values.

legend

either logical or a list specifying any of the components decribed in the colorkey section of levelplot.

verbose

should some details be printed during the process

layer.name

the name of the layer to be shown on the map

gdal

logical. If TRUE (default) gdal_translate is used to create the png file for display when possible. See details for further information.

...

arguments passed on to respective methods

r

integer. Index of the Red channel, between 1 and nlayers(x)

g

integer. Index of the Green channel, between 1 and nlayers(x)

b

integer. Index of the Blue channel, between 1 and nlayers(x)

zcol

attribute name or column number in attribute table of the column to be rendered

Details

If the raster object is not in memory (i.e. if raster::inMemory is FLASE) and argument gdal is set to TRUE (default) gdal_translate is used to translate the rsater object to a png file to be rendered in the viewer/browser. This is fast for large rasters. In this case, argument maxpixels is not used, instead the image is rendered in original resolution. However, this means that RasterLayers will be shown in greyscale. If you want to set a color palette manually, use gdal = FALSE and (optionally provide) col.regions.

For plainView there are a few keyboard shortcuts defined:

  • plus/minus - zoom in/out

  • space - toggle antialiasing

  • esc - zoom to layer extent

  • enter - set zoom to 1

  • ctrl - increase panning speed by 10

Methods (by class)

Author

Stephan Woellauer

Tim Appelhans

Examples

if (interactive()) {

  # RasterLayer
  plainView(poppendorf[[4]])

  # RasterStack
  plainview(poppendorf, r = 4, g = 3, b = 2) # true color
  plainview(poppendorf, r = 5, g = 4, b = 3) # false color

}