Add Geometric Features to Spatial Grid Cells

Creates multilinestring sf objects representing geometric features (crosses or diagonals) within the centre of each grid cell in an input spatial grid.

Usage

add_cross_to_grid(sf_object = NULL)

add_diagonals_to_grid(sf_object = NULL)

Arguments

sf_object

An sf object (tibble) with polygon geometries representing grid cells. If NULL, the function stops with an error.

Value

• add_cross_to_grid: An sf object with multilinestring geometries representing crosses in the centre of each grid cell, retaining the input CRS.

• add_diagonals_to_grid: An sf object with multilinestring geometries representing diagonal and off-diagonal lines for each grid cell, retaining the input CRS.

Details

The following functions are included:

• add_cross_to_grid: Creates a multilinestring sf object with crosses (horizontal and vertical lines) in the centre of each grid cell.

• add_diagonals_to_grid: Creates a multilinestring sf object with diagonal and off-diagonal lines for each grid cell.

Note

The functions require the sf, dplyr, purrr, tibble, and tidyr packages to be installed and loaded.

Author

Ahmed El-Gabbas

Examples

# loading packages
ecokit::load_packages(dplyr, sf, ggplot2)

# ---------------------------------------------
# Create a 5x5 grid
# ---------------------------------------------

grid_original <- sf::st_make_grid(
    sf::st_bbox(c(xmin = 0, ymin = 0, xmax = 10, ymax = 10), crs = 4326),
    n = c(5, 5)) %>%
  sf::st_sf(geometry = .)

# ---------------------------------------------
# Add crosses to grid
# ---------------------------------------------

grid_cross <- add_cross_to_grid(grid_original)
ggplot2::ggplot() +
  ggplot2::geom_sf(
    data = grid_original, mapping = ggplot2::aes(), color = "black",
    linewidth = 0.75, fill = "transparent") +
  ggplot2::geom_sf(
    data = grid_cross, mapping = ggplot2::aes(), color = "red",
    linewidth = 0.75, inherit.aes = TRUE, linetype = 3) +
  ggplot2::scale_x_continuous(expand = c(0, 0, 0, 0), limits = c(0, 10)) +
  ggplot2::scale_y_continuous(expand = c(0, 0, 0, 0), limits = c(0, 10)) +
  ggplot2::theme_minimal()


# ---------------------------------------------
# Add diagonals to grid
# ---------------------------------------------

grid_diagonals <- add_diagonals_to_grid(grid_original)
ggplot2::ggplot() +
  ggplot2::geom_sf(
    data = grid_original, mapping = ggplot2::aes(), color = "black",
    linewidth = 0.75, fill = "transparent") +
  ggplot2::geom_sf(
    data = grid_diagonals, mapping = ggplot2::aes(), color = "red",
    linewidth = 0.75, inherit.aes = TRUE, linetype = 3) +
  ggplot2::scale_x_continuous(expand = c(0, 0, 0, 0), limits = c(0, 10)) +
  ggplot2::scale_y_continuous(expand = c(0, 0, 0, 0), limits = c(0, 10)) +
  ggplot2::theme_minimal()