GNU Octave Manual Version 3 by John W. Eaton, David Bateman, Søren Hauberg Paperback (6"x9"), 568 pages ISBN 095461206X RRP £24.95 ($39.95) |
28.4 Interpolation on Scattered Data
An important use of the Delaunay tessellation is that it can be used to
interpolate from scattered data to an arbitrary set of points. To do
this the N-simplex of the known set of points is calculated with
delaunay
, delaunay3
or delaunayn
. Then the
simplices in which the desired points are found are
identified. Finally the vertices of the simplices are used to
interpolate to the desired points. The functions that perform this
interpolation are griddata
, griddata3
and
griddatan
.
- Function File: zi = griddata (x, y, z, xi, yi, method)
- Function File: [xi, yi, zi] = griddata (x, y, z, xi, yi, method)
-
Generate a regular mesh from irregular data using interpolation. The function is defined by
z = f (x, y)
. The interpolation points are all(xi, yi)
. If xi, yi are vectors then they are made into a 2D mesh.The interpolation method can be
"nearest"
,"cubic"
or"linear"
. If method is omitted it defaults to"linear"
.See also delaunay
- Function File: vi = griddata3 (x, y, z, v xi, yi, zi, method, options)
-
Generate a regular mesh from irregular data using interpolation. The function is defined by
y = f (x,y,z)
. The interpolation points are all xi.The interpolation method can be
"nearest"
or"linear"
. If method is omitted it defaults to"linear"
.See also griddata, delaunayn
- Function File: yi = griddatan (x, y, xi, method, options)
-
Generate a regular mesh from irregular data using interpolation. The function is defined by
y = f (x)
. The interpolation points are all xi.The interpolation method can be
"nearest"
or"linear"
. If method is omitted it defaults to"linear"
.See also griddata, delaunayn
An example of the use of the griddata
function is
rand("state",1); x=2*rand(1000,1)-1; y=2*rand(size(x))-1; z=sin(2*(x.^2+y.^2)); [xx,yy]=meshgrid(linspace(-1,1,32)); griddata(x,y,z,xx,yy);
that interpolates from a random scattering of points, to a uniform grid.
ISBN 095461206X | GNU Octave Manual Version 3 | See the print edition |