Get SpatialPolygons polylabelr coordinate

Get SpatialPolygons polylabelr coordinate

sp_polylabelr(sp, apply_holes = TRUE, ...)

Arguments

sp

sp::SpatialPolygons object

apply_holes

logical indicating whether to apply any polygon holes when present in sp.

...

additional arguments are ignored

Value

list with items x with x coordinate, y with y coordinate, and dist with distance to the enclosing polygon.

Details

This function is a simple wrapper function around polylabelr::poi() for sp::SpatialPolygons input. This function does two things:

1. It finds the largest polygon in the sp::SpatialPolygons input, which may contain multiple disconnected polygons.

2. It applies "holes" inside the polygon when present, to prevent the label from being chosen inside the hole.

See also

Other venndir label: draw_gridtext_groups(), polygon_label_fill(), polygon_label_outside(), polygon_label_segment()

Examples

setlist <- list(A=letters, B=sample(letters, 4));
vo <- venndir(setlist, proportional=TRUE, do_plot=FALSE);
sp <- vo$venn_spdf[1,];
plot(sp, col="gold")
xy <- sp_polylabelr(sp);
points(xy, pch=20, cex=4, col="navy")


# example with a hole inside
sp <- sp_ellipses(xcenter=1, ycenter=1, xradius=0.5, yradius=1);
sp_hole <- sp_ellipses(xcenter=1, ycenter=1, xradius=0.2, yradius=0.5);
sp_donut <- rgeos::gDifference(sp, sp_hole);
plot(sp_donut, col="gold")
spt <- sp_polylabelr(sp_donut);
text(x=spt$x, y=spt$y, add=TRUE, labels="label")