Extract a list of arcs from a triangulation object.

This function extracts a list of arcs from a triangulation object created by tri.mesh.

arcs(tri.obj)

Arguments

tri.obj: object of class triSht

Details

This function acesses the arcs component of a triangulation object returned by tri.mesh and extracts the arcs contained in this triangulation. This is e.g. used for plotting.

Value

A matrix with two columns "from" and "to" containing the indices of points connected by the arc with the corresponding row index.

Author

Albrecht Gebhardt <albrecht.gebhardt@aau.at>, Roger Bivand <roger.bivand@nhh.no>

Examples

data(franke)
tr <- tri.mesh(franke$ds3)
arcs(tr)
#>       from to
#>  [1,]   11  4
#>  [2,]    4  1
#>  [3,]    1 11
#>  [4,]   11 12
#>  [5,]   12  4
#>  [6,]    4  8
#>  [7,]    8  1
#>  [8,]    4  6
#>  [9,]    6 10
#> [10,]   10  4
#> [11,]   12  6
#> [12,]    5 16
#> [13,]   16 12
#> [14,]   12  5
#> [15,]   11  5
#> [16,]   16  6
#> [17,]   10  8
#> [18,]    3  6
#> [19,]    6 13
#> [20,]   13  3
#> [21,]   16 21
#> [22,]   21  6
#> [23,]   22 17
#> [24,]   17 16
#> [25,]   16 22
#> [26,]    5 22
#> [27,]   10  3
#> [28,]    3  8
#> [29,]   21 17
#> [30,]   17 15
#> [31,]   15 21
#> [32,]   21 13
#> [33,]   22 19
#> [34,]   19 17
#> [35,]    5 25
#> [36,]   25 22
#> [37,]   15 13
#> [38,]   23 15
#> [39,]   17 23
#> [40,]    3  2
#> [41,]    2  8
#> [42,]   13  9
#> [43,]    9  3
#> [44,]   13 14
#> [45,]   14  9
#> [46,]   15 14
#> [47,]   23 18
#> [48,]   18 15
#> [49,]   19 23
#> [50,]    7 19
#> [51,]   19 25
#> [52,]   25  7
#> [53,]    5  7
#> [54,]   18 14
#> [55,]   19 24
#> [56,]   24 23
#> [57,]    9  2
#> [58,]   20  9
#> [59,]   14 20
#> [60,]   18 20
#> [61,]   24 20
#> [62,]   18 24
#> [63,]   24  9
#> [64,]    7 24