PBSmapping (version 2.72.1)

appendPolys: Append a Two-Column Matrix to a PolySet

Description

Append a two-column matrix to a PolySet, assigning PID and possibly SID values automatically or as specified in its arguments.

Usage

appendPolys (polys, mat, PID = NULL, SID = NULL, isHole = FALSE)

Arguments

polys

existing PolySet; if NULL, creates a new PolySet (required).

mat

two-column matrix to append (required).

PID

new polygon's PID.

SID

new polygon's SID.

isHole

Boolean value; if TRUE, mat represents a hole.

Value

PolySet containing mat appended to polys. The function retains attributes from polys.

Details

If the PID argument is NULL, the appended polygon's PID will be one greater than the maximum within polys (if defined); otherwise, it will be 1.

If polys contains an SID column and the SID argument equals NULL, this function uses the next available SID for the corresponding PID.

If polys does not contain an SID column and the caller passes an SID argument, all existing polygons will receive an SID of 1. The new polygon's SID will match the SID argument.

If isHole = TRUE, the polygon's POS values will appropriately represent a hole (reverse order of POS).

If (PID, SID) already exists in the PolySet, the function will issue a warning and duplicate those identifiers.

See Also

addPolys, clipPolys, closePolys, convLP, fixBound, fixPOS, joinPolys, plotMap, plotPolys.

Examples

# NOT RUN {
local(envir=.PBSmapEnv,expr={
  #--- create two simple matrices
  a <- matrix(data=c(0,0,1,0,1,1,0,1),ncol=2,byrow=TRUE);
  b <- matrix(data=c(2,2,3,2,3,3,2,3), ncol=2,byrow=TRUE);
  #--- build a PolySet from them
  polys <- appendPolys(NULL, a);
  polys <- appendPolys(polys, b);
  #--- print the result
  print (polys);
})
# }

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