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Prepare an sf object for use with dragmapr

Source: R/spatial_io.R
prepare_dragmapr_sf.Rd

Repairs invalid geometry, filters to polygon types, assigns a fallback CRS when none is present, and reprojects geographic (longitude/latitude) data to a projected CRS so metre offsets work correctly. CRS-less inputs trigger a warning because the fallback is an assumption; pass target_crs explicitly when your data uses a different projected CRS.

Usage

prepare_dragmapr_sf(x, target_crs = 3857)

Arguments

x

An sf object.

target_crs

EPSG code for the projected CRS to use when the input is geographic. Defaults to 3857 (Web Mercator).

Value

A projected sf object containing only polygon or multipolygon features with valid geometry.

See also

read_dragmapr_sf_upload() and read_dragmapr_sf_url() to read spatial files before passing them to this function; drag_map_prototype() which requires a projected sf object.

Examples

poly <- sf::st_sf(
  region = "A",
  geometry = sf::st_sfc(
    sf::st_polygon(list(rbind(c(-1,0),c(1,0),c(1,1),c(-1,1),c(-1,0)))),
    crs = 4326
  )
)
out <- prepare_dragmapr_sf(poly)
#> dragmapr: transforming from geographic to EPSG:3857 for metre offsets.
sf::st_is_longlat(out)  # FALSE
#> [1] FALSE