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Automatic repair of polygon geometries

Source: R/st_prepair.R
st_prepair.Rd

Repair polygon geometries according to the international standards ISO 19107 using a constrained triangulation approach (van Oosterom et al. 2005; Ledoux et al. 2014)

Usage

st_prepair(x)

Arguments

x

sf::st_sf(), sf::st_sfc() or sfg object (containing POLYGON or MULTIPOLYGON geometries).

Value

A sf::st_sf(), sf::st_sfc() or sfg

object (same as the argument to x).

Details

The function supports two algorithms:

  • oddeven: an extension of the odd-even algorithm to handle polygons containing inner rings and degeneracies;

  • setdiff: one where we follow a point set difference rule for the rings (outer - inner).

References

Ledoux H, Arroyo Ohori K, and Meijers M (2014) A triangulation-based approach to automatically repair GIS polygons. Computers & Geosciences 66:121--131.

van Oosterom P, Quak W, and Tijssen T (2005) About Invalid, Valid and Clean Polygons In: Developments in Spatial Data Handling. Springer, Berlin, Heidelberg

See also

See sf::st_make_valid() for another approach to repair polygon geometries.

Examples

# \dontrun{
# create an object containing a broken polygon geometry
x <- sf::st_as_sfc("POLYGON((0 0, 0 10, 10 0, 10 10, 0 0))")

# check if this polygon is indeed broken
sf::st_is_valid(x)
#> [1] FALSE

# repair the polygon
y <- st_prepair(x)
#> Linking to GEOS 3.11.1, GDAL 3.6.4, PROJ 9.3.1; sf_use_s2() is TRUE

# check that the repaired polygon has been fixed
print(st_is_valid(y))
#> [1] TRUE
# }