[vtkusers] Interpolation of data..

[Bill Lorensen]

The last part of this example:
http://www.vtk.org/Wiki/VTK/Examples/InterpolateTerrain
does what you want.

Basically,
1) Add the lat/log and elevations to a polydata
2) Create a surface with Delaunay2D
3) Add the points with unknown elevation to a vtkPoints
4) Use a cell locator to cast infinite rays into the surface to find
the elevation.


On Fri, Apr 23, 2010 at 9:50 PM, Rakesh Patil <rakeshthp at in.com> wrote:
>
>
> Well,
>
> I was trying with this example:
>
> http://www.vtk.org/Wiki/VTK/Examples/InterpolateTerrain
>
> In this example, there are two ways specified for interpolation.. One is
> using
> vtkProbeFilter and another is using vtkCellLocator
>
> First i tried using vtkProbeFilter. But failed getting the output.. But
> using the
> vtkCellLocator, i was able to produce interpolated values for the third
> column of MeshG.
>
> After observation, i foound that only the region which is common in both the
> grids,
> was interpolated. So i was fully stuck wondering how to find the remaining
> values..
>
> any comments..??
>
> Thanks
>
> Rakesh Patil
>
> ---------- Original message ----------
> From:"Dean Inglis"< dean.inglis at camris.ca >
> Date: 23 Apr 10 23:59:48
> Subject: Re: Re:[vtkusers]Interpolation of data..
> To: "Rakesh Patil"
>
> How can you expect your mesh to get interpolated
> when its z coordinate values are all 0
> but the scatter data range in z from -700 to -900?
> The bounds of each unstructured grid do not even
> overlap / intersect!
>
> Dean
>
>> Hi,My both the meshes are unstructured grid. My application is based on
>> FEA method.. ScatterG does contains scalars and the depth values are
>> stored as a scalar array for scatterG..I dont want coordinate values to be
>> interpolated.. As an example,scatterG contains data something like
>> this,Points: 87.23 16.2690086.24 17.8753087.18 17.27700......and the
>> scalar for scatterG is defined as 900530700......meshG contains
>> points84.1217.83 081.3315.28 083.2418.28 0......So,, what i want to do is,
>> using the third column of scatterG, i need to estimate the third column of
>> meshG..Any ideas how it can be done.??ThanksRakesh Patil Original message
>> From:"De an Inglis"< dean.inglis at camris.ca >Date: 23 Apr 10
>> 20:16:47Subject:Re: Re:[vtkusers]Interpolation of data..To: "Rakesh Patil"
>> vtkProbeFlter will probe the scalar values ateach spatial location of your
>> scattered points: youneed to have scalar, vector, or tensor data
>> associatedwith the grid's points:scatterG>GetPointData()>SetScalars(
>> somevt
>> kDataArray );the vtkProbeFilter will not interpolate any coordinatevalues
>> like x , y,z locations.If you have depth valuesin a vtkDataArray that
>> correspond to the x, y, z locationsin your scatterG grid, then this should
>> work.Does anyone know ifmaybe the input to the probe filter needs to be a
>> structured data set likevtkPolyData? By the sound of your grid's name
>> "mesh" , this sounds like structureddata.Can it be converted to a
>> vtkPolyData?Also, you allocate a smart pointer as:vtkSmartPointer probe =
>> vtkSmartPointer: :New()Dean Original Message From: "Rakesh Patil" To: Cc:
>> Sent: Friday, April 23, 2010 9:40 AMSubject: Re: Re:[vtkusers]
>> Interpolation of data..> Hi..I can independently view those grids... This
>> is what I have done..vtkUnstructuredGrid *scatterG =
>> MyApp::getInstance()>getScatterGrid();vtkUnstructuredGrid *meshG =
>> MyApp::getInstance()>getMeshGrid();vtkSmartPointer probe =
>>
>> vtkSmartPointer::New();probe>SetSource(scatterG);probe>SetInput(meshG);probe>Update();vtkDataArr
>> ay *data = probe>GetOutput()>GetPointData()>GetScalar();vtkDoubleArray
>> *doubleArray =
>>
>> vtkDoubleArray::SafeDownCast(data);MyContour::getInstance()>setDisplayArray(doubleArray);After
>> doing this, i click on contour display button, and the contour for
>> bathymetry gets displayed for meshG.Initially, meshG doesnt have
>> depth/elevation (z) value. z value is always 0 for every node point. x and
>> y corresponds to the lon and lat respectively.But the scatter data
>> contains lon, lat, and depth.. So, once the interpolation is done, i
>> should get the bathymetry (depth/elevation) for meshG also..'MyContour' in
>> the above code is the class which displays the contours for wh> atever
>> data is being passed.So, any suggestions or > comments..??ThanksRegards
>> Rakesh Patil Original messageFrom:Dean Inglis< > dean.inglis at camris.ca >
>> Date: 23 Apr 10 16:49:50 Subject:Re: > Re:[vtkusers]Interpolation of
>> data.. To: "Rakesh Patil">
>>
>
>
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