calcMidRange function

Calculate the Midpoint of the X/Y Ranges of Polygons

Calculate the midpoint of the X/Y ranges of polygons found in a PolySet .

calcMidRange (polys, rollup = 3)

Arguments

• polys: PolySet to use.
• rollup: level of detail in the results; 1 = PIDs only, 2 = outer contours only, and 3 = no roll-up.

Details

If rollup equals 1, the results contain a mean range 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 mean range for each unique (PID, SID).

Returns

PolyData with columns PID, SID (may be missing), X, and Y.

Author(s)

Nicholas M. Boers, Staff Software Engineer

Jobber, Edmonton AB

Last modified Rd: 2013-04-10

See Also

calcArea, calcCentroid, calcLength, calcSummary.

Examples

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(calcMidRange(nepacLL[is.element(nepacLL$PID,c(33,39,47)),]))
})