[vtkusers] Interpolation of data..

Mon Apr 26 08:05:46 EDT 2010

What values would you expect in area where you have no elevation data?

Maybe I misunderstand the problem.

On Sun, Apr 25, 2010 at 9:45 PM, Rakesh Patil <rakeshthp at in.com> wrote:
>
>
> Hi,
>
> So, you mean there is no other way..?? extrapolation or anything..??
>
> In that case i need to write my own filter to do this then..??
>
> Thanks
>
> Regards
> Rakesh Patil
> ---------- Original message ----------
> From:Bill Lorensen< bill.lorensen at gmail.com >
> Date: 26 Apr 10 02:13:14
> Subject: Re: [vtkusers] Interpolation of data..
> To: Rakesh Patil
>
> 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 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/lo g 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 uns tructured 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"
>>>& gt; 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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>>
>