Compute Geometric Boundaries — bounding

From a vector of geometries identify different types of boundaries.

Usage

bounding_boxes(x)

bounding_rect(x)

minimum_rotated_rect(x)

convex_hull(x)

concave_hull(x, concavity)

extreme_coords(x)

bounding_box(x)

Arguments

x: an object of class rsgeo
concavity: a value between 0 and 1 specifying the concavity of the convex hull

Value

bounding_box() returns a named vector of xmin, ymin, xmax, and ymax
bounding_boxes() returns a list of bounding box numeric vectors for each geometry
bounding_rect() returns an rs_POLYGON of the bounding rectangle of each geometry
convex_hull() returns an rs_POLYGON of the convex hull for each geometry
concave_hull() returns an rs_POLYGON of the specified concavity for each geometry
extreme_coords() returns the extreme coordinates of each geometry as a list where each element is a named vector of xmin, ymin, xmax, and ymax where each element is a Point geometry of the extreme value
minimum_rotated_rect() returns the minimum rotated rectangle covering a geometry as an rs_POLYGON

Details

Note that if you want a convex or concave hull over an entire vector of geometries you must first union or combine them using either combine_geoms() or union_geoms()

Examples

lns <- geom_linestring(
  1:20,
  runif(20, -5, 5),
  rep.int(1:5, 4)
)
bounding_box(lns)
#>      xmin      ymin      xmax      ymax 
#>  1.000000 -4.435066 20.000000  4.073953 
bounding_boxes(lns)
#> [[1]]
#>      xmin      ymin      xmax      ymax 
#>  1.000000 -2.509600 16.000000  1.351401 
#> 
#> [[2]]
#>      xmin      ymin      xmax      ymax 
#>  2.000000 -3.248156 17.000000  1.194972 
#> 
#> [[3]]
#>      xmin      ymin      xmax      ymax 
#>  3.000000 -4.435066 18.000000  2.367154 
#> 
#> [[4]]
#>      xmin      ymin      xmax      ymax 
#>  4.000000 -3.958552 19.000000  2.627060 
#> 
#> [[5]]
#>      xmin      ymin      xmax      ymax 
#>  5.000000 -3.009242 20.000000  4.073953 
#> 
minimum_rotated_rect(lns)
#> <rs_POLYGON[5]>
#> [1] Polygon { exterior: LineString([Coord { x: 16.000000000000004, y: -0.16407...
#> [2] Polygon { exterior: LineString([Coord { x: 17.000000000000004, y: 1.194972...
#> [3] Polygon { exterior: LineString([Coord { x: 18.000000000000004, y: 1.616737...
#> [4] Polygon { exterior: LineString([Coord { x: 3.9999999999999982, y: -3.95855...
#> [5] Polygon { exterior: LineString([Coord { x: 20.071459638340365, y: 3.556851...
convex_hull(lns)
#> <rs_POLYGON[5]>
#> [1] Polygon { exterior: LineString([Coord { x: 11.0, y: -2.509599975310266 }, ...
#> [2] Polygon { exterior: LineString([Coord { x: 7.0, y: -2.723288901615888 }, C...
#> [3] Polygon { exterior: LineString([Coord { x: 8.0, y: -4.435065584257245 }, C...
#> [4] Polygon { exterior: LineString([Coord { x: 19.0, y: -1.3721352722495794 },...
#> [5] Polygon { exterior: LineString([Coord { x: 10.0, y: -3.0092415190301836 },...
concave_hull(lns, 0.5)
#> <rs_POLYGON[5]>
#> [1] Polygon { exterior: LineString([Coord { x: 11.0, y: -2.509599975310266 }, ...
#> [2] Polygon { exterior: LineString([Coord { x: 7.0, y: -2.723288901615888 }, C...
#> [3] Polygon { exterior: LineString([Coord { x: 8.0, y: -4.435065584257245 }, C...
#> [4] Polygon { exterior: LineString([Coord { x: 19.0, y: -1.3721352722495794 },...
#> [5] Polygon { exterior: LineString([Coord { x: 10.0, y: -3.0092415190301836 },...
extreme_coords(lns)
#> [[1]]
#> <rs_POINT[4]>
#>                                              xmin 
#> Point(Coord { x: 1.0, y: 1.3514011376537383 }))   
#>                                              ymin 
#> Point(Coord { x: 11.0, y: -2.509599975310266 }))  
#>                                              xmax 
#> Point(Coord { x: 16.0, y: -0.1640706416219473 })) 
#>                                              ymax 
#> Point(Coord { x: 1.0, y: 1.3514011376537383 }))   
#> 
#> [[2]]
#> <rs_POINT[4]>
#>                                             xmin 
#> Point(Coord { x: 2.0, y: -1.9498682138510048 })) 
#>                                             ymin 
#> Point(Coord { x: 12.0, y: -3.248156241606921 })) 
#>                                             xmax 
#> Point(Coord { x: 17.0, y: 1.1949720559641719 })) 
#>                                             ymax 
#> Point(Coord { x: 17.0, y: 1.1949720559641719 })) 
#> 
#> [[3]]
#> <rs_POINT[4]>
#>                                             xmin 
#> Point(Coord { x: 3.0, y: 2.36715373583138 }))    
#>                                             ymin 
#> Point(Coord { x: 8.0, y: -4.435065584257245 }))  
#>                                             xmax 
#> Point(Coord { x: 18.0, y: 1.6167376027442515 })) 
#>                                             ymax 
#> Point(Coord { x: 3.0, y: 2.36715373583138 }))    
#> 
#> [[4]]
#> <rs_POINT[4]>
#>                                              xmin 
#> Point(Coord { x: 4.0, y: -3.958551676478237 }))   
#>                                              ymin 
#> Point(Coord { x: 4.0, y: -3.958551676478237 }))   
#>                                              xmax 
#> Point(Coord { x: 19.0, y: -1.3721352722495794 })) 
#>                                              ymax 
#> Point(Coord { x: 9.0, y: 2.627060494851321 }))    
#> 
#> [[5]]
#> <rs_POINT[4]>
#>                                              xmin 
#> Point(Coord { x: 5.0, y: 4.073952937033027 }))    
#>                                              ymin 
#> Point(Coord { x: 10.0, y: -3.0092415190301836 })) 
#>                                              xmax 
#> Point(Coord { x: 20.0, y: 1.4740854036062956 }))  
#>                                              ymax 
#> Point(Coord { x: 5.0, y: 4.073952937033027 }))    
#>