R/polyg.R

In espadon: Easy Study of Patient DICOM Data in Oncology

polyg.area <- function(pol) {
  
  pol_le <- nrow(pol)
  pol <- round(pol, 6)
  if (!all(pol[1,] == pol[pol_le,])) return(0.0)
  idx <- 2:pol_le
  return(abs(sum(pol[idx - 1, 1] * pol[idx, 2] - pol[idx, 1] * pol[idx - 1, 2]) / 2))
}