Creates a plot sample on a regular grid with a random start location.
Arguments
- spdf
A
SpatialPointsDataFrame
defining the points that are to be sampled by the plot sample.- boundary
A
SpatialPolygonsDataFrame
defining the survey boundary within which the points occur.- x.ppn
The proportion of the x=axis that is to be included in the plots.
- y.ppn
The proportion of the y=axis that is to be included in the plots.
- nx
The number of plots in the x-dimension.
- ny
The number of plots in the y-dimension.
Value
A list with three components:
plots
:A
SpatialPolygonsDataFrame
object containing the plots that were sampled.dets
:A
SpatialPointsDataFrame
object containing the locations of the points within the plots.counts
:A
dataframe
containing the following columnsx
:The x-coordinates of the centres of the plots within the boundary.
y
:The y-coordinates of the centres of the plots within the boundary.
n
:The numbers of points in each plot.
area
:The areas of the plots within the boundary
.
Examples
# \donttest{
# Some features require the raster package
if (require("raster", quietly = TRUE) &&
require("ggplot2", quietly = TRUE)) {
data(gorillas, package = "inlabru")
plotpts <- plotsample(gorillas$nests, gorillas$boundary,
x.ppn = 0.4, y.ppn = 0.4, nx = 5, ny = 5
)
ggplot() +
gg(plotpts$plots) +
gg(plotpts$dets, pch = "+", cex = 2) +
gg(gorillas$boundary)
}
#> Regions defined for each Polygons
#> Regions defined for each Polygons
# }