spCircle: Create a Circular Spatial Object

In sampSurf: Sampling Surface Simulation for Areal Sampling Methods

Description

This function simply creates a circular polygon object that is of class "SpatialPolygons". It also creates a "SpatialPoints" object holding the center point of the circle.

Usage

spCircle(radius,
         spUnits = CRS(projargs = as.character(NA)),
         centerPoint = c(x = 0, y = 0),
         nptsPerimeter = 100,
         spID = paste("circle", .StemEnv$randomID(), sep = ":"),
         ...)

Arguments

radius	The radius of the circle in the appropriate units.
spUnits	Object of class "CRS": A legal proj.4 coordinate system; the default is to have user-defined coordinates.
centerPoint	The circle's center location in the appropriate units. This is a vector of length two with names "x" and "y".
nptsPerimeter	The number of points forming the perimeter of the polygon.
spID	A unique identifier that will be used in displaying the spatial polygon.
...	Not used currently.

Details

The polygon created for the circle will always have the individual internal "Polygon" object named ‘pgCircle’, while the internal "Polygons" object will be named ‘pgsCircle’. These may need to be renamed in the returned object to make more sense. See the sp package for more details.

Value

A list with the following components...

spCircle	The "SpatialPolygons" polygon object.
location	The "SpatialPoints" point object.

Author(s)

Jeffrey H. Gove

See Also

The standingTree constructor.

Examples

dbh = 20
sp.dbh = spCircle(dbh/2, centerPoint=c(x=30,y=80), spID='tree.1') 
plot(sp.dbh$spCircle)
plot(sp.dbh$location, add=TRUE, pch=3)

Example output

Loading required package: sp
Loading required package: raster
Loading required package: rasterVis
Loading required package: lattice
Loading required package: latticeExtra
Loading required package: RColorBrewer
Loading required package: boot

Attaching package: 'boot'

The following object is masked from 'package:lattice':

    melanoma

sampSurf version 0.7-3 (2015-04-14)

sampSurf documentation built on March 5, 2021, 5:06 p.m.