Sample points within JamPolygon

Sample points within JamPolygon

sample_JamPolygon(
  jp,
  n = 100,
  xyratio = 1.1,
  spread = TRUE,
  n_ratio = 1,
  pattern = c("offset", "rectangle"),
  buffer = 0,
  byCols = c("-y", "x"),
  do_plot = FALSE,
  verbose = FALSE,
  ...
)

Arguments

jp

JamPolygon

n

integer number of points required

xyratio

numeric adjustment for the x/y ratio, numbers larger than 1 make the x-axis spacing larger than the y-axis spacing.

spread

logical (default TRUE) when more then n points can be fit inside the polygon, spread=TRUE spreads the points evenly across the available points, while spread=FALSE simply uses the first n points.

n_ratio

numeric ratio which must be 1 or higher, indicating how many total sampled points should be defined, before choosing the points to use. This option is used only when spread=TRUE, which causes more points to be defined, from which it uses evenly distributed values.

pattern

character string indicating how to array the points:

• "offset" (default) uses a rectangular grid where alternating points on each row are offset slightly on the y-axis.

• "rectangle" uses a rectangular grid with points on each row that share the same y-axis value.

buffer

numeric optional buffer used to adjust the jp polygon size overall, where negative values will slightly shrink the polygon border. Points are sampled after this adjustment.

byCols

character passed to jamba::mixedSortDF() to determine how to sort the resulting coordinates. Default byCols=c("-y", "x") sorts top-to-bottom, then left-to-right.

do_plot

logical indicating whether to create a plot to illustrate the process.

verbose

logical indicating whether to print verbose output.

...

additional arguments are ignored.

Details

This function arrays points across solid portions of polygons provided in jp.

Todo:

1. Enable polygon buffer to guarantee minimum spacing from borders.

2. Allow different spatial patterns, currently square or rectangular. In future, consider hexagonal, diamond, or diagonal.

See also

Other JamPolygon: JamPolygon-class, Venndir-class, [,JamPolygon,ANY,ANY,ANY-method, add_orientation_JamPolygon(), area_JamPolygon(), bbox_JamPolygon(), buffer_JamPolygon(), check_JamPolygon(), check_Venndir(), eulerr_to_JamPolygon(), farthest_point_JamPolygon(), find_venn_overlaps_JamPolygon(), has_point_in_JamPolygon(), intersect_JamPolygon(), label_fill_JamPolygon(), label_outside_JamPolygon(), label_segment_JamPolygon(), labelr_JamPolygon(), minus_JamPolygon(), nearest_point_JamPolygon(), nudge_JamPolygon(), plot.JamPolygon(), point_in_JamPolygon(), polyclip_to_JamPolygon(), polygon_circles(), polygon_ellipses(), split_JamPolygon(), union_JamPolygon(), update_JamPolygon()

Examples

df3 <- data.frame(name=c("polygon1", "polygon2"),
   label=c("polygon1", "polygon2"),
   x=I(list(
      list(c(1, 6, 6, 1),
         c(2, 5, 5, 2),
         c(3, 4, 4, 3)),
      list(#c(11, 16, 16, 11),
         c(12, 15, 15, 12),
         c(13, 14, 14, 13))
      )),
   y=I(list(
      list(c(1, 1, 6, 6),
         c(2, 2, 5, 5),
         c(3, 3, 4, 4)),
      list(#c(1, 1, 6, 6),
         c(2, 2, 5, 5),
         c(3, 3, 4, 4))
      )),
   fill=c("gold", "firebrick"))
jp3 <- new("JamPolygon", polygons=df3);

sample_JamPolygon(jp3[1,], n=40, do_plot=TRUE)

sample_JamPolygon(jp3[1,], n=80, do_plot=TRUE)


sample_JamPolygon(jp3[1,], n=40, xyratio=1.5, do_plot=TRUE)


sample_JamPolygon(jp3[1,], n=40, xyratio=1/1.5, do_plot=TRUE)