spatialEco (version 0.1-5)

parea.sample: Percent area sample

Description

Creates a point sample of polygons where n is based on percent area

Usage

parea.sample(x, pct = 0.1, join = FALSE, msamp = 1, sf = 4046.86, stype = "hexagonal", ...)

Arguments

x

sp SpatialPolygonsDataFrame object

pct

Percent of area sampled

join

Join polygon attributed to point sample

msamp

Minimum samples

sf

Scaling factor (default is meters to acres conversion factor)

stype

Sampling type ('random', 'regular', 'nonaligned', 'hexagonal')

...

Additional arguments passed to spsample

Value

A SpatialPointsDataFrame with polygon samples

Examples

require(sp)
sr1=Polygons(list(Polygon(cbind(c(180114, 180553, 181127, 181477, 181294, 181007, 180409, 
  180162, 180114), c(332349, 332057, 332342, 333250, 333558, 333676, 
  332618, 332413, 332349)))),'1')
sr2=Polygons(list(Polygon(cbind(c(180042, 180545, 180553, 180314, 179955, 179142, 179437, 
  179524, 179979, 180042), c(332373, 332026, 331426, 330889, 330683, 
  331133, 331623, 332152, 332357, 332373)))),'2')
sr=SpatialPolygons(list(sr1,sr2))
srdf=SpatialPolygonsDataFrame(sr, data.frame(row.names=c('1','2'), PIDS=1:2))

ars <- parea.sample(srdf, pct=0.20, stype='random') 
  plot(srdf)
    plot(ars, pch=20, add=TRUE)