Calculate the Centroids of Polygons
Calculate the centroids of polygons found in a PolySet.
calcCentroid (polys, rollup = 3)
polys |
PolySet to use. |
rollup |
level of detail in the results; |
If rollup equals 1, the results contain a centroid for
each unique PID only. When it equals 2, they contain
entries for outer contours only. Finally, setting it to 3
prevents roll-up, and they contain a centroid for each unique
(PID, SID).
PolyData with columns PID, SID (may be missing),
X, and Y.
Nicholas M. Boers, Associate Professor – Computer Science
MacEwan University, Edmonton AB
Last modified Rd: 2013-04-10
local(envir=.PBSmapEnv,expr={
#--- load the data (if using R)
if (!is.null(version$language) && (version$language=="R"))
data(nepacLL,envir=.PBSmapEnv)
#--- calculate and print the centroids for several polygons
print(calcCentroid(nepacLL[is.element(nepacLL$PID,c(33,39,47)),]))
})Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.