Thin a PolySet of Polygons
Thin a PolySet, where each unique (PID, SID)
describes a polygon.
thinPolys (polys, tol = 1, filter = 3)
polys |
PolySet to thin. |
tol |
tolerance (in kilometres when |
filter |
minimum number of vertices per result polygon. |
This function executes the Douglas-Peuker line simplification
algorithm on each polygon within polys.
PolySet containing the thinned data. The function recalculates
the POS values for each polygon.
Nicholas M. Boers, Associate Professor – Computer Science
MacEwan University, Edmonton AB
Last modified Rd: 2013-04-10
local(envir=.PBSmapEnv,expr={
oldpar = par(no.readonly=TRUE)
#--- load the data (if using R)
if (!is.null(version$language) && (version$language=="R"))
data(nepacLL,envir=.PBSmapEnv)
#--- plot a thinned version of Vancouver Island (3 km tolerance)
plotMap(thinPolys(nepacLL[nepacLL$PID == 33, ], tol = 3))
#--- add the original Vancouver Island in a different line type to
#--- emphasize the difference
addPolys(nepacLL[nepacLL$PID == 33, ], border=2, lty=8, density=0)
par(oldpar)
})Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.