relate function

Spatial relationships between geometries

relate returns a logical matrix indicating the presence or absence of a specific spatial relationships between the geometries in x and y.

is.related returns a logical vector indicating the presence or absence of a specific spatial relationships between x and any of the geometries in y. methods

## S4 method for signature 'SpatVector,SpatVector'
relate(x, y, relation, pairs=FALSE, na.rm=TRUE)

## S4 method for signature 'SpatVector,missing'
relate(x, y, relation, pairs=FALSE, na.rm=TRUE)

## S4 method for signature 'SpatVector,SpatVector'
is.related(x, y, relation)

Arguments

• x: SpatVector or SpatExtent
• y: missing or as for x
• relation: character. One of "intersects", "touches", "crosses", "overlaps", "within", "contains", "covers", "coveredby", "disjoint", or "equals". It can also be a "DE-9IM" string such as "FFFF***". See Wikipedia or GeoTools doc
• pairs: logical. If TRUE a two-column matrix is returned with the indices of the cases where the requested relation is TRUE. This is especially helpful when dealing with many geometries as the returned value is generally much smaller
• na.rm: logical. If TRUE and pairs=TRUE, geometries in x for which there is no related geometry in y are omitted

Returns

matrix (relate) or vector (is.related)

See Also

compareGeom to check if the geometries are identical (equivalent to the "equals" relation)

adjacent, nearby, intersect, crop

Examples

# polygons
p1 <- vect("POLYGON ((0 0, 8 0, 8 9, 0 9, 0 0))")
p2 <- vect("POLYGON ((5 6, 15 6, 15 15, 5 15, 5 6))")
p3 <- vect("POLYGON ((8 2, 9 2, 9 3, 8 3, 8 2))")
p4 <- vect("POLYGON ((2 6, 3 6, 3 8, 2 8, 2 6))")
p5 <- vect("POLYGON ((2 12, 3 12, 3 13, 2 13, 2 12))")
p6 <- vect("POLYGON ((10 4, 12 4, 12 7, 11 7, 11 6, 10 6, 10 4))")

p <- rbind(p1, p2, p3, p4, p5, p6)
plot(p, col=rainbow(6, alpha=.5))
lines(p, lwd=2)
text(p)

## relate SpatVectors
relate(p1, p2, "intersects")
relate(p1, p3, "touches")
relate(p1, p5, "disjoint")
relate(rbind(p1, p2), p4, "disjoint")

## relate geometries within SpatVectors
# which are completely separated?
relate(p, relation="disjoint")

# which touch (not overlap or within)?
relate(p, relation="touches")
# which overlap (not merely touch, and not within)?
relate(p, relation="overlaps")
# which are within (not merely overlap)?
relate(p, relation="within")

# do they touch or overlap or are within?
relate(p, relation="intersects")

all(relate(p, relation="intersects") == 
  (relate(p, relation="overlaps") | 
   relate(p, relation="touches") |
   relate(p, relation="within")))

#for polygons, "coveredby" is "within"
relate(p, relation="coveredby")

# polygons, lines, and points 

pp <- rbind(p1, p2)
L1 <- vect("LINESTRING(1 11, 4 6, 10 6)")
L2 <- vect("LINESTRING(8 14, 12 10)")
L3 <- vect("LINESTRING(1 8, 12 14)")
lns <- rbind(L1, L2, L3)
pts <- vect(cbind(c(7,10,10), c(3,5,6)))

plot(pp, col=rainbow(2, alpha=.5))
text(pp, paste0("POL", 1:2), halo=TRUE)
lines(pp, lwd=2)
lines(lns, col=rainbow(3), lwd=4)
text(lns, paste0("L", 1:3), halo=TRUE)
points(pts, cex=1.5)
text(pts, paste0("PT", 1:3), halo=TRUE, pos=4)

relate(lns, relation="crosses")
relate(lns, pp, relation="crosses") 
relate(lns, pp, relation="touches") 
relate(lns, pp, relation="intersects") 

relate(lns, pp, relation="within")
# polygons can contain lines or points, not the other way around
relate(lns, pp, relation="contains") 
relate(pp, lns, relation="contains") 
# points and lines can be covered by polygons
relate(lns, pp, relation="coveredby")

relate(pts, pp, "within")
relate(pts, pp, "touches")
relate(pts, lns, "touches")