griddata : error in use due to facet being coplanar

I was wondering if anyone can decipher an error message I get when I send 3 tables into griddata. The x, y, and z tables are 61x63 and I am trying to get values at vectors x_vctr, y_vctr via : gi=griddata(x,y,z,x_vctr,y_vctr,'linear'); I have a doc file with the complete message but it begins :

??? qhull precision error: initial facet 2 is coplanar with the interior point
ERRONEOUS FACE
While executing:  | qhull d Qt Qbb Q
Options selected for Qhull 2003.1 2003/12/30:
  delaunay  Qtriangulate  Qbbound-last  Qcoplanar-keep  _pre-merge
  _zero-centrum  Pgood  Qinterior-keep  _max-width 3.7e+003
  Error-roundoff 6.1e-012  _one-merge 4.3e-011  Visible-distance 1.2e-011
  U-coplanar-distance 1.2e-011  Width-outside 2.4e-011  _wide-facet 7.3e-011
precision problems (corrected unless 'Q0' or an error)
      2
 flipped facets
The input to qhull appears to be less than 3 dimensional, or a
computation has overflowed.

Qhull could not construct a clearly convex simplex from points:

The center point is coplanar with a facet, or a vertex is coplanar
with a neighboring facet.  The maximum round off error for
computing distances is 6.1e-012.  The center point, facets and distances
to the center point are:

Thanks

Answer 1

[Walter Roberson]

You might have to send x(:), y(:), and z(:) as the arrays