calcMidRange: Calculate the Midpoint of the X/Y Ranges of Polygons

In PBSmapping: Mapping Fisheries Data and Spatial Analysis Tools

Calculate the Midpoint of the X/Y Ranges of Polygons

Description

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

Usage

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).

Value

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)),]))
})

PBSmapping documentation built on Sept. 30, 2024, 9:21 a.m.