contoursToSP03.r

for (i in 1:length(poly_volcano))
{
  temp <- poly_volcano@polygons[[i]]@Polygons
  for (j in 1:length(temp))
  {
    if (length(temp) > 1)
    {
      for (k in 1:length(temp))
      {
        if (j != k)
        {
          pol_main <- temp[[j]]
          pol_comp <- temp[[k]]
          val <- point.in.polygon(point.x = pol_comp@coords[1,1], point.y = pol_comp@coords[1,2],
                                  pol.x   = pol_main@coords[,1],  pol.y   = pol_main@coords[,2])
          if (val == 1)
          {
            poly_volcano@polygons[[i]]@Polygons[[k]]@hole <- T
            poly_volcano@polygons[[i]]@Polygons[[k]]@coords <- poly_volcano@polygons[[i]]@Polygons[[k]]@coords[nrow(poly_volcano@polygons[[i]]@Polygons[[k]]@coords):1,]
          }
        }
      }
    }
  }
}

png("volcano03.png", 200, 200)
par(oma = c(0,0,0,0), mar = c(0,0,0,0))
plot(poly_volcano, col = terrain.colors(length(poly_volcano)), border = NA)
dev.off()