Convert a data.frame of boundary points into a SpatialPolgonsDataFrame
Source:R/bru.spatial.R
spoly.Rd
A polygon can be described as a sequence of points defining the polygon's boundary.
When given such a sequence (anti clockwise!) this function creates a
SpatialPolygonsDataFrame holding the polygon decribed. By default, the
first two columns of data
are assumed to define the x and y coordinates
of the points. This behavior can ba changed using the cols
parameter, which
points out the names of the columns holding the coordinates. The coordinate
reference system of the resulting spatial polygon can be set via the crs
paraemter. Posterior conversion to a different CRS is supported using the
to.crs
parameter.
Arguments
- data
A data.frame of points describing the boundary of the polygon
- cols
Column names of the x and y coordinates within the data
- crs
Coordinate reference system of the points
- to.crs
Coordinate reference system for the SpatialLines ouput.
Examples
# \donttest{
# Create data frame of boundary points (anti clockwise!)
pts <- data.frame(
x = c(1, 2, 1.7, 1.3),
y = c(1, 1, 2, 2)
)
# Convert to SpatialPolygonsDataFrame
pol <- spoly(pts)
if (require(ggplot2, quietly = TRUE) &&
require(ggpolypath, quietly = TRUE)) {
# Plot it!
ggplot() +
gg(pol)
}
#> Regions defined for each Polygons
# }