Generate a Hexagonal Lattice

This function generates a hexagonal lattice of points within the given x and y limits, using a specified hexagon diameter. The diameter is 2 times the distance between adjacent x (and y) values, see examples.

Usage

grid_hex(xlim, ylim, d)

Arguments

xlim

A numeric vector of length 2 specifying the x-axis limits.

ylim

A numeric vector of length 2 specifying the y-axis limits.

d

A numeric value specifying the hexagon diameter.

Value

A data frame with two columns, x and y, containing the coordinates of the hexagonal grid points.

Examples

xlim <- c(-1, 1)
ylim <- c(-1, 0)

grid <- grid_hex(xlim, ylim, .25)

head( grid )
#>       x          y
#> 1 -1.00 -0.8660254
#> 2 -0.75 -0.8660254
#> 3 -0.50 -0.8660254
#> 4 -0.25 -0.8660254
#> 5  0.00 -0.8660254
#> 6  0.25 -0.8660254
str( grid )
#> 'data.frame':	43 obs. of  2 variables:
#>  $ x: num  -1 -0.75 -0.5 -0.25 0 0.25 0.5 0.75 1 -0.875 ...
#>  $ y: num  -0.866 -0.866 -0.866 -0.866 -0.866 ...
plot( grid, asp = 1 )


diff(sort(unique(grid$x)))
#>  [1] 0.125 0.125 0.125 0.125 0.125 0.125 0.125 0.125 0.125 0.125 0.125 0.125
#> [13] 0.125 0.125 0.125 0.125