Generate Many Tile Maps — many

Generate, plot, and compare many tile maps.

many_maps(
  data,
  labels,
  square = TRUE,
  flat_topped = FALSE,
  prop = c(0, 0.05),
  interpolate = c(0.5, 1),
  smoothness = c(0, 5),
  shift = list(c(0, 0), c(0.5, 0), c(0, 0.5)),
  weights = c(1, 1, 1, 1),
  plot = TRUE,
  size = 2
)

Arguments

data	An object of class `sfc_MULTIPOLYGON` or `sfc_POLYGON`, which contains the regions that make up the original map.
labels	A character vector with the labels of the regions. Labels must be in the same order as regions given for `data` argument.
square	logical. If `TRUE`, generates a square tile map. If `FALSE`, generates a hexagon tile map.
flat_topped	logical. If `TRUE`, hexagons are flat-topped. If `FALSE`, hexagons are pointy-topped.
prop	A numeric vector of proportions used in specifying the standard deviation of the Gaussian noise added to original region centroids. The standard deviation of the Gaussian noise is calculated as the mean distance between a region centroid and its neighboring regions' centroids multiplied by the value provided for the `prop` argument. A different set of noisy region centroids is created for each given value.
interpolate	A numeric vector of values between 0 and 1 controlling the linear interpolation between the noisy region centroids and fully-transformed region centroids. If 0, noisy region centroids are used. If 1, fully-transformed centroids are used. A different set of interpolated centroids is created for each given value.
smoothness	numeric vector. Controls the bandwidth of the Gaussian kernel used for smoothing the transformed boundary polygon. The bandwidth is calculated as the mean distance between adjacent boundary points multiplied by the value provided for the `smoothness` argument. A different transformed boundary is created for each given value.
shift	A list of numeric vectors of length two specifying the number of grid steps to shift the candidate tile map in the x and y directions before counting the number of tile centroids that lie within the transformed boundary. A different final tile map is created for each given value.
weights	A numeric vector of length 4 specifying the weights used for calculating the total cost. The first, second, third, and fourth weights are applied to the location, adjacency, angle, and roughness costs, respectively.
plot	logical. If `TRUE`, prints plot of generated tile maps.
size	numeric. Controls size of labels in plot.

Value

Returns a data.frame in which each row corresponds to one map and the columns contain the generated maps, the parameters used for creating the maps, and the costs associated with each map. The data.frame is ordered by the total cost.

Details

Generates many candidate tile maps using an algorithm proposed in "Generating Tile Maps" (McNeill and Hale 2017). The regions of the map must be contiguous. Coordinates cannot be in terms of latitude and longitude. Instead the coordinate reference system must be an appropriate planar projection. The number of maps generated is equal to the product of the lengths of the prop, interpolate, smoothness, and shift arguments.

References

McNeill, Graham, and Scott A Hale. 2017. “Generating Tile Maps.” In Computer Graphics Forum, 36:435–45. 3. Wiley Online Library.

Examples

library(sf)
northeast <- governors[c(6,7,17,18,19,27,28,30,36,37,43),]
ne_maps <- many_maps(northeast$geometry, northeast$abbreviation,
                     prop = 0, interpolate = 1, smoothness = c(0,20),
                     shift = list(c(0,0), c(0,0.5)))