Check validity or make an invalid geometry valid

Checks whether a geometry is valid, or makes an invalid geometry valid

st_is_valid(x, ...)

# S3 method for sfc
st_is_valid(x, ..., NA_on_exception = TRUE, reason = FALSE)

# S3 method for sf
st_is_valid(x, ...)

# S3 method for sfg
st_is_valid(x, ...)

st_make_valid(x)

# S3 method for sfg
st_make_valid(x)

Arguments

x	object of class sfg, sfg or sf
...	passed on to sfc method
NA_on_exception	logical; if TRUE, for polygons that would otherwise raise a GEOS error (exception, e.g. for a POLYGON having more than zero but less than 4 points, or a LINESTRING having one point) return an NA rather than raising an error, and suppress warning messages (e.g. about self-intersection); if FALSE, regular GEOS errors and warnings will be emitted.
reason	logical; if TRUE, return a character with, for each geometry, the reason for invalidity, NA on exception, or "Valid Geometry" otherwise.

Value

st_is_valid returns a logical vector indicating for each geometries of x whether it is valid.

Object of the same class as x

Details

st_make_valid uses the lwgeom_makevalid method also used by the PostGIS command ST_makevalid if the GEOS version linked to is smaller than 3.8.0, and otherwise the version shipped in GEOS.

Examples

p1 = st_as_sfc("POLYGON((0 0, 0 10, 10 0, 10 10, 0 0))")
st_is_valid(p1)
#> [1] FALSE
st_is_valid(st_sfc(st_point(0:1), p1[[1]]), reason = TRUE)
#> [1] "Valid Geometry"         "Self-intersection[5 5]"
library(sf)
x = st_sfc(st_polygon(list(rbind(c(0,0),c(0.5,0),c(0.5,0.5),c(0.5,0),c(1,0),c(1,1),c(0,1),c(0,0)))))
suppressWarnings(st_is_valid(x))
#> [1] FALSE
y = st_make_valid(x)
st_is_valid(y)
#> [1] TRUE
y %>% st_cast()
#> Geometry set for 2 features 
#> Geometry type: GEOMETRY
#> Dimension:     XY
#> Bounding box:  xmin: 0 ymin: 0 xmax: 1 ymax: 1
#> CRS:           NA
#> POLYGON ((0.5 0, 0 0, 0 1, 1 1, 1 0, 0.5 0))
#> LINESTRING (0.5 0, 0.5 0.5)