Test whether geometries are well formed

TRUE when a geometry satisfies the OGC simple features rules.

Returns the first validation problem it finds, or NA when the geometry is valid.

Usage

ga_is_valid(geometry)

ga_validation_error(geometry)

Arguments

geometry

a GeoArrow geometry array

Value

a boolean array of the same length as geometry

a string array of the same length as geometry

Details

Several algorithms give wrong answers on invalid input rather than failing, so check validity before trusting a result. Common problems are a polygon whose rings self intersect, a ring with too few points, and a coordinate that is NaN or infinite.

ga_is_valid() returns NA for a null geometry. Use ga_validation_error() to see why a geometry is invalid.

A geometry can break more than one rule; ga_validation_error() reports only the first, since you often resolve the rest by fixing it.

References

Validation

See also

Other validation: ga_make_valid()

Examples

square <- rbind(c(0, 0), c(2, 0), c(2, 2), c(0, 2), c(0, 0))
bowtie <- rbind(c(0, 0), c(2, 2), c(2, 0), c(0, 2), c(0, 0))
good <- sf::st_polygon(list(square))
bad <- sf::st_polygon(list(bowtie))
g <- geoarrow::as_geoarrow_array(sf::st_sfc(good, bad))

as.vector(ga_is_valid(g))
#> [1]  TRUE FALSE
as.vector(ga_validation_error(g))
#> [1] NA                                     
#> [2] "exterior ring has a self-intersection"