convCP function

Convert Contour Lines into a PolySet

Convert output from contourLines into a PolySet .

convCP (data, projection = NULL, zone = NULL)

Arguments

• data: contour line data, often from the contourLines function.
• projection: optional projection attribute to add to the PolySet.
• zone: optional zone attribute to add to the PolySet.

Details

data contains a list as described below. The contourLines function create a list suitable for the data argument.

A three-element list describes each contour. The named elements in this list include the scalar level, the vector x, and the vector y. Vectors x and y must have equal lengths. A higher-level list (data) contains one or more of these contours lists.

Returns

A list with two named elements PolySet and PolyData . The PolySet element contains a PolySet representation of the contour lines. The PolyData element links each contour line (PID, SID) with a level.

Author(s)

Nicholas M. Boers, Staff Software Engineer

Jobber, Edmonton AB

Last modified Rd: 2013-04-10

See Also

contour, contourLines, convLP, makeTopography.

Examples

local(envir=.PBSmapEnv,expr={
  oldpar = par(no.readonly=TRUE)
  #--- create sample data for the contourLines() function
  x <- seq(-0.5, 0.8, length=50);  y <- x
  z <- outer(x, y, FUN = function(x,y) { sin(2*pi*(x^2+y^2))^2; } )
  data <- contourLines(x, y, z, levels=c(0.2, 0.8))
  #--- pass that sample data into convCP()
  result <- convCP(data)
  #--- plot the result
  plotLines(result$PolySet, projection=1)
  print(result$PolyData)
  par(oldpar)
})