pwl_interp_2d_scattered

pwl_interp_2d_scattered, a MATLAB code which produces a piecewise linear (PWL) interpolant to 2D scattered data, that is, data that is not guaranteed to lie on a regular grid.

This program computes a Delaunay triangulation of the data points, and then constructs an interpolant triangle by triangle. Over a given triangle, the interpolant is the linear function which matches the data already given at the vertices of the triangle.

The code requires the r8lib() library. The test code requires the TEST_INTERP_2D library.

Licensing:

The information on this web page is distributed under the MIT license.

Languages:

pwl_interp_2d_scattered is available in a C version and a C++ version and a Fortran90 version and a MATLAB versionand an Octave version.

Related Data and Programs:

pwl_interp_2d_scattered_test

lagrange_interp_2d, a MATLAB code which defines and evaluates the Lagrange polynomial p(x,y) which interpolates a set of data depending on a 2D argument that was evaluated on a product grid, so that p(x(i),y(j)) = z(i,j).

pwl_interp_2d, a MATLAB code which evaluates a piecewise linear interpolant to data defined on a regular 2D grid.

rbf_interp_2d, a MATLAB code which defines and evaluates radial basis function (RBF) interpolants to scattered 2D data.

shepard_interp_2d, a MATLAB code which defines and evaluates Shepard interpolants to scattered 2D data, based on inverse distance weighting.

test_interp_2d, a MATLAB code which defines test problems for interpolation of regular or scattered data z(x,y), depending on a 2D argument.

triangulation, a MATLAB code which performs various operations on order 3 (linear) or order 6 (quadratic) triangulations.

triangulation_order3_contour, a MATLAB code which makes contour plot of scattered data, or of data defined on an order 3 triangulation.

vandermonde_interp_2d, a MATLAB code which finds a polynomial interpolant to data z(x,y) of a 2D argument by setting up and solving a linear system for the polynomial coefficients, involving the Vandermonde matrix.

Source Code:

• diaedg.m, chooses a diagonal edge.
• i4_sign.m, returns the sign of an integer.
• i4mat_transpose_print.m, prints the transpose of an I4MAT.
• i4mat_transpose_print_some.m, prints some of the transpose of an I4MAT.
• i4vec_heap_d.m, rearranges an I4VEC into a descending heap.
• i4vec_sort_heap_a.m, ascending heap sorts an I4VEC.
• i4vec_sorted_unique.m, returns the unique elements of a sorted I4VEC.
• lrline.m, determines if a point lies to the left or right of a directed line.
• perm_check2.m, checks a permutation.
• perm_inverse.m, finds the inverse of a permutation.
• pwl_interp_2d_scattered_value.m, evaluates a piecewise linear interpolant to scattered 2D data.
• r8tris2.m, returns the Delaunay triangulation of a set of points in 2D.
• swapec.m, determines which of two diagonals of a quadrilateral should to use in a mesh.
• triangulation_order3_print.m, prints information about an order 3 triangulation;
• triangulation_search_delaunay.m, finds the triangle containing a point, using a Delaunay search;
• vbedg.m, determines which edges are visible to a point.