[vtkusers] Interpolation of data..

[Bill Lorensen]

If you do not have data in a region, I don't see how you can interpolate it.

On Sun, Apr 25, 2010 at 1:54 PM, Rakesh Patil <rakeshthp at in.com> wrote:
>
>
> Hi Bill,
>
> Thanks for your reply.. I implemented that technique and it works fine. As i
> said in my previous post, outsid range values are not interpolated.
>
> For example, pls see the attached image file for reference.. In the figure,
> the mesh which is generated, doesnt completely fall in the area of the
> scatter data..
> In the rwo white patches, the values are not interpolated. I mean i dont get
> the actual result there in those areas (as there is no scatter points avail
> there)
>
> So, what can i do to get values for my entire mesh instead of getitng for
> partial mesh.??Either interolation or extrapolation.. Any means is available
> in VTK
> to implement this..??
>
> Thanks
>
> Regards
> Rakesh Patil
> ---------- Original message ----------
> From:Bill Lorensen< bill.lorensen at gmail.com >
> Date: 24 Apr 10 18:15:33
> Subject: Re: [vtkusers] Interpolation of data..
> To: Rakesh Patil
>
> 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 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 meth od.. 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
>>> asso ciatedwith 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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