The gappiness a of shape — gappiness • orange

Proportion of gap cells

Usage

gappiness(x, s, ...)

# S4 method for class 'character,trigrid'
gappiness(x, s, exclude = NULL, full = FALSE)

# S4 method for class 'matrix,trigrid'
gappiness(
  x,
  s,
  long = NULL,
  lat = NULL,
  duplicates = FALSE,
  plot = FALSE,
  plot.args = NULL,
  full = FALSE,
  exclude = NULL
)

Arguments

x: The list of faces that are part of the shape.
s: Spatial discretization strucutre (currently only trigrid-class icosahedral grid).
...: Arguments passed to class-specific methods.
exclude: The list of faces that is to be excluded from the calculation
full: logical, should only the estimate (FALSE) be returned, or additional data as well?(TRUE).
long: character, column name of the longitudes.
lat: character, column name of the latitudes.
duplicates: logical, should identical coordinates be included in the calculation (default is FALSE)
plot: Logical, should the result be plotted? Will plot over active plot (as in add=TRUE), if here is any.
plot.args: List arguments passed to the plotting function: plot.

Value

A proportion that gives the ratio of hole-cells compared to all occupied cells.

Details

Gappiness refers to proporion of area that are covered by the internal gaps that defined by a set of discretized cells or a point set that covers some cells in a discretization structre.

Examples

# 1. Only cells
# create a grid
hex <- hexagrid(2, sf=TRUE)

# an example shape
shape <- paste0("F", c(4, 5, 11, 13, 15, 21, 24, 26, 32, 33, 34, 35, 36))
plot(hex, border="gray80")
plot(hex, shape, col="red", add=TRUE)

# the gappiness
gap <- gappiness(shape, hex, full=TRUE)
gap
#> $estimate
#> [1] 0.2777778
#> 
#> $holes
#> F12 F14 F23 F25 F22 
#>   1   2   1   2   1 
#> 
#> $occupied
#>  [1] "F4"  "F5"  "F11" "F13" "F15" "F21" "F24" "F26" "F32" "F33" "F34" "F35"
#> [13] "F36"
#> 
# plot the first gap
plot(hex, names(gap$holes[gap$holes==1]), col="#00555577", add=TRUE)


# points
set.seed(7)
rand <- icosa::rpsphere(20, output="polar")
occ <- locate(hex, rand)
plot(hex, border="gray80")
plot(hex, occ, col="red", add=TRUE)
points(rand, col="green", pch=3, cex=2)

# gappiness
gap <- gappiness(occ, hex, full=TRUE)
plot(hex, names(gap$holes), col="orange", add=TRUE)