triangles(tri.obj)
tri.obj
|
object of class "tri"
|
tri.mesh.
The vertices in the returned matrix (let's denote it with
retval) are ordered
counterclockwise with the first vertex taken
to be the one with smallest index. Thus,
retval[i,"node2"] and retval[i,"node3"] are larger
than
retval[i,"node3"] and index adjacent neighbors of
node retval[i,"node1"]. The columns trx and
arcx, x=1,2,3 index the triangle and arc,
respectively, which are opposite (not shared
by) node nodex, with trix= 0 if
arcx indexes a boundary arc. Vertex
indexes range from 1 to N, triangle indexes
from 0 to NT, and, if included, arc indexes
from 1 to NA = NT+N-1. The triangles are
ordered on first (smallest) vertex indexes,
except that the sets of constraint triangles
(triangles contained in the closure of a constraint
region) follow the non-constraint
triangles.
node1,node2,node3,
representing the vertex nodal indexes,
tr1,tr2,tr3, representing neighboring triangle
indexes and arc1,arc2,arc3 reresenting arc indexes.
Each row represents one triangle.
tri, print.tri, plot.tri, summary.tri, triangles# we will use the test data from library(akima): library(akima) data(akima) akima.tr<-tri.mesh(akima$x,akima$y) triangles(akima.tr)