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Extract spatial grid points within a specified boundary

Source: R/get_grid_points.R
get_grid_points.Rd

Extract spatial grid points from a gridded SpatRaster object that fall within the boundary of a specified spatial object (e.g., county, city, ZIP code, etc.). The output can be limited to points strictly within the boundary or include all masked points overlapping the boundary extent.

Usage

get_grid_points(
  gridded_data,
  sf_boundary,
  boundary_name,
  boundary_col_name,
  output = c("within", "masked")
)

Arguments

gridded_data

A SpatRaster object containing gridded time series data (e.g., temperature).

sf_boundary

An sf object containing the boundaries of interest. This object must contain the boundary specified by boundary_name in the column identified by boundary_col_name. For Virginia, the sf_va_county dataset provided in this package may be used.

boundary_name

Character string. Name of the boundary to extract. Must match an entry in the boundary_col_name column of sf_boundary.

boundary_col_name

Name of the column in sf_boundary that contains boundary_name.

output

Character string indicating the type of output. "within" (default) returns only grid points strictly within the boundary, "masked" returns all points from the masked raster (may include edge pixels).

Value

  • output = "within": A tibble of grid points strictly within the specified boundary.

  • output = "masked": A sf object of all points from the masked raster (may include edge pixels).

Examples

library(sf)
#> Linking to GEOS 3.12.1, GDAL 3.8.4, PROJ 9.4.0; sf_use_s2() is TRUE

richmond_msa <- load_era5_temperature()
va_county <- sf_va_county

masked_output <- get_grid_points(gridded_data = richmond_msa,
                                 sf_boundary = va_county,
                                 boundary_name = "Amelia County",
                                 boundary_col_name = county,
                                 output = "masked")
#> Warning: Expected 2 pieces. Missing pieces filled with `NA` in 45 rows [21, 45, 69, 93,
#> 117, 141, 165, 189, 213, 237, 261, 285, 309, 333, 357, 381, 405, 429, 453, 477,
#> ...].

within_output <- get_grid_points(gridded_data = richmond_msa,
                                 sf_boundary = va_county,
                                 boundary_name = "Amelia County",
                                 boundary_col_name = county,
                                 output = "within")
#> Warning: Expected 2 pieces. Missing pieces filled with `NA` in 45 rows [21, 45, 69, 93,
#> 117, 141, 165, 189, 213, 237, 261, 285, 309, 333, 357, 381, 405, 429, 453, 477,
#> ...].