# triSht: A triangulation object In interp: Interpolation Methods

## Description

R object that represents the triangulation of a set of 2D points, generated by tri.mesh.

## Arguments

 n Number of nodes x x coordinates of the triangulation nodes y y coordinates of the triangulation nodes nt number of triangles trlist Matrix of indices which defines the triangulation, each row corresponds to a triangle. Columns i1, i2, i3 of the row i contain the node indices defining the ith triangle. Columns j1, j2, j3 of the row i contain the indices of neighbour triangles (or 0 if no neighbour available along the convex hull). Columns k1, k2, k3 of the row i contain the indices of the arcs of the ith triangle as returned by the arcs function. cclist Matrix describing the circumcircles and triangles. Columns x and y contain coordinates of the circumcircle centers, r is the circumcircle radius. area is the triangle area and ratio is the ratio of the radius of the inscribed circle to the circumcircle radius. It takes it maximum value 0.5 for an equilateral triangle. The radius of the inscribed circle can be get via r_i=\frac{r}{ratio}. nchull number of points on the convex hull chull A vector containing the indices of nodes forming the convec hull (in counterclockwise ordering). narcs number of arcs forming the triangulation arcs A matrix with node indices describing the arcs, contains two columns from and to. call call, which generated this object

## Note

This object is not backward compatible with tri objects generated from package tripack but the functions and methods are! So you have to regenerate these objects and then you can continue to use the same calls as before.

The only difference is that no constraints to the triangulation are possible in package interp.

## Author(s)

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

tri.mesh, print.triSht, plot.triSht, summary.triSht