Spatial Select

Performs a spatial select (feature subset) between a polygon(s) and other feature class

Performs a spatial select of features based on an overlay of a polygon (x), which can represent multiple features, and a polygon, point or line feature classes (y). User can specify a partial or complete intersection, using within argument, or within a distance, using distance argument, predicated on the query polygon. This function is similar to ArcGIS/Pro spatial select. Please note that for point to point neighbor selections use the knn function.

spatial.select(
  x,
  y = NULL,
  distance = NULL,
  predicate = c("intersect", "contains", "covers", "touches", "proximity",
    "contingency"),
  neighbors = c("queen", "rook")
)

Arguments

x	An sp or sf polygon(s) object that defines the spatial query
y	A sp or sf feature class that will be subset by the query of x
distance	A proximity distance of features to select (within distance)
predicate	Spatial predicate for intersection
neighbors	If predicate = "contingency" type of neighbors options are c("queen", "rook")

Value

An sp object representing a subset of y based on the spatial query of x or, if predicate = contingency a sparse matrix representing neighbor indexes

Note

Valid spatial predicates include: intersect, touches, covers, contains, proximity and contingency. See [DE-9IM topology model](https://en.wikipedia.org/wiki/DE-9IM) for detailed information on data predicates.

Author

Jeffrey S. Evans <jeffrey_evans@tnc.org>

Examples

library(raster)
library(sp)   

data(meuse)
  coordinates(meuse) <- ~x+y

spolys <- hexagons(meuse, res=100)
p <- raster(extent(spolys), res=800)
  p[] <- runif(ncell(p)) * 10
    p <- rasterToPolygons(p, fun=function(x){x > 6})
  
#### On polygons   
sub.int <- spatial.select(p, spolys, predicate = "intersect")
sub.contains <- spatial.select(p, spolys, predicate = "contains")
sub.cov <- spatial.select(p, spolys, predicate = "covers")
sub.touches <- spatial.select(p, spolys, predicate = "touches")
sub.prox <- spatial.select(p, spolys, distance=100, predicate = "proximity")

opar <- par(no.readonly=TRUE)
par(mfrow=c(2,3))
  plot(spolys, main="all data")
    plot(p, add=TRUE)  
  plot(sub.int, main="intersects")
    plot(p, add=TRUE) 
  plot(sub.contains, main="contains")
    plot(p, add=TRUE) 
  plot(sub.cov, main="covers")
    plot(p, add=TRUE)    
  plot(sub.touches, main="touches")
    plot(p, add=TRUE)   
  plot(sub.prox, main="Proximity 100m distance")
    plot(p, add=TRUE) 
par(opar)

#### On points 
#### note; touches is not relevant for points and intersect/contains/covers 
####       yield the same results  
sub.int <- spatial.select(p, meuse, predicate = "intersect")
sub.contains <- spatial.select(p, meuse, predicate = "contains")
sub.prox <- spatial.select(p, meuse, distance=200, predicate = "proximity")

opar <- par(no.readonly=TRUE)
par(mfrow=c(2,2))
  plot(meuse, main="all data", pch=20)
    plot(p, add=TRUE)  
  plot(sub.int, main="intersects", pch=20)
    plot(p, add=TRUE) 
  plot(sub.contains, main="contains", pch=20)
    plot(p, add=TRUE) 
  plot(sub.prox, main="Proximity 200m distance", pch=20)
    plot(p, add=TRUE)
par(opar)

#### For rook or queen polygon contingency   
spolys <- as(sf::st_make_grid(sf::st_sfc(sf::st_point(c(0,0)), 
             sf::st_point(c(3,3))), n = c(3,3)), "Spatial")

spatial.select(spolys, predicate = "contingency")
#> Sparse geometry binary predicate list of length 9, where the predicate was `relate_pattern'
#>  1: 2, 4, 5
#>  2: 1, 3, 4, 5, 6
#>  3: 2, 5, 6
#>  4: 1, 2, 5, 7, 8
#>  5: 1, 2, 3, 4, 6, 7, 8, 9
#>  6: 2, 3, 5, 8, 9
#>  7: 4, 5, 8
#>  8: 4, 5, 6, 7, 9
#>  9: 5, 6, 8
spatial.select(spolys, predicate = "contingency", neighbors = "rook") 
#> Sparse geometry binary predicate list of length 9, where the predicate was `relate_pattern'
#>  1: 2, 4
#>  2: 1, 3, 5
#>  3: 2, 6
#>  4: 1, 5, 7
#>  5: 2, 4, 6, 8
#>  6: 3, 5, 9
#>  7: 4, 8
#>  8: 5, 7, 9
#>  9: 6, 8

Arguments

Value

Note

See also

Author

Examples