Raster* in the raster package.
Adding methods for list, SpatialPolygons, SpatialLines,
and SpatialPoints, gg, histogram, igraph.
These latter classes return 1.## S3 method for class 'list':
nlayers(x)## S3 method for class 'SpatialPolygons':
nlayers(x)
## S3 method for class 'SpatialLines':
nlayers(x)
## S3 method for class 'SpatialPoints':
nlayers(x)
## S3 method for class 'gg':
nlayers(x)
## S3 method for class 'histogram':
nlayers(x)
## S3 method for class '.spadesPlot':
nlayers(x)
## S3 method for class 'igraph':
nlayers(x)
.spadesPlotObjects object or list of these.