plotKML (version 0.2-4)

kml_layer.SpatialPixels: Writes SpatialPixels or SpatialGrid objects to KML

Description

Writes sp classes "SpatialGrid" or "SpatialPixels" to PNG images and makes a KML document (ground overlays). Target attributes can be specified using aesthetics arguments (e.g. "colour").

Usage

kml_layer.SpatialPixels(obj, raster_name, plot.legend = TRUE, metadata = NULL, ...)

Arguments

obj

object of class "RasterLayer", "SpatialPixelsDataFrame" or "SpatialGridDataFrame"

plot.legend

logical; specify whether a map legend should be generated automatically

metadata

(optional) specify the metadata object

raster_name

(optional) specify the output file name (PNG)

...

additional aesthetics arguments

Details

Google Earth does not properly handle a 24-bit PNG file which has a single transparent color (read more at http://groups.google.com/group/earth-help/{Google Earth Help}). To force transparency, plotKML will try to set it using the -matte -transparent "#FFFFFF" option in the http://www.imagemagick.org/Usage/masking/{ImageMagick convert program} (ImageMagick needs to be installed separately and located using plotKML.env()). The PNG export uses the 'cairographics', which will never use a palette and normally creates a larger 32-bit ARGB file, but then always allows transparancy.

See Also

kml-methods, kml_open, kml_layer.Raster

Examples

data(eberg_grid)
coordinates(eberg_grid) <- ~x+y
gridded(eberg_grid) <- TRUE
proj4string(eberg_grid) <- CRS("+init=epsg:31467")
data(SAGA_pal)
# KML plot with a single raster:
kml(eberg_grid, colour_scale = SAGA_pal[[1]], colour = TWISRT6) 
# factor-type variable:
kml(eberg_grid, colour_scale = SAGA_pal[[1]], colour = LNCCOR6)