Create sampling sites within hexagons

Creates a grid of sites within the hexagon grid cells created by create_hexes(). These sites can then be sampled with sample_sites().

Usage

create_sites(hexes, spacing = NULL, n = NULL, hex_id = hex_id)

Arguments

hexes

Spatial Data frame. Hexagon grid across sampling region. Requires column identifying the hexagon IDs (see hex_id)

spacing

Numeric. Distance between sites. Units are assumed to be those of hex spatial data frame.

n

Numeric. Approximate number of sites to create within a hex grid.

hex_id

Column. Identifies hexagon IDs (e.g., default hex_id).

Value

Spatial data frame of sites as points.

Examples

# Get sites by exact within-hex distances
sites_sp <- create_sites(psu_hexagons, spacing = 5)

# Get sites by approximate number of points (but equal spacing among hexes)
sites_n <- create_sites(psu_hexagons, n = 61)

# Same number of sites, but in slightly different spots, because creating by
# n maximizes spacing, but creating by spacing using the exact spacing
# specified.

library(ggplot2)
ggplot() +
  geom_sf(data = psu_hexagons) +
  geom_sf(data = sites_sp, size = 0.5, colour = "red") +
  geom_sf(data = sites_n, size = 0.5, colour = "blue")