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Data interpolation

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  • Subject: [mg96220] Data interpolation
  • From: hemanth korrapati <hemanthkorrapati at>
  • Date: Mon, 9 Feb 2009 05:37:52 -0500 (EST)


I have some 3D point data acquired through a laser range finder. The
data is sparse.  I need to construct a height field out of this data
and as a part of this i have to interpolate heights at some locations
{x,y} where the actual data is not available.
I want to use B-splines. But it seems that B-splines require uniformly
distributed control points, which is not the case with my data.
My data cannot form a uniform table which is required by the
BSplineSurface function if I sort my data.

for some data i got the following error:
Interpolation::indim: The coordinates do not lie on a structured
tensor product grid. >>

So I started using the "ListDensityPlot" function which does a linear
interpolation of the data. The interpolation is sufficiently good. But
I would like to get an output consisting of list of tuples like
{x,y,InterpolatedHeight} at the desired {x,y} locations. Right now I
can only see the plot but cannot get the interpolated heights at
desired locations({x,y}).

Now I have three questions:
1) how do i make my data usable for splines in mathematica ?
2) how do i get the interpolated values at desired {x,y} using
"ListDensityPlot" function ?
3) Is there a better way other than the above two methods to
interpolate the missing data ?

Thank you

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