[vtkusers] VTK class to do interpolation of scalar values

Mon Dec 7 15:53:17 EST 2009

Your data points seem to all have a z=0.0. If they are scattered in 3D
space, then Delaunay3D might do the trick.

Bill

On Mon, Dec 7, 2009 at 3:49 PM, Jesse Kim <jinryongkim at gmail.com> wrote:
> Bill,
>
> Thanks so much for your help.
>
> I think this what I wanted to get. However, I have one more question for
> you. Is there any way I can express them in 3D like isosurface? Should I
> change it to delaunay3D?
>
> Thanks,
>
> Jesse
>
> Bill Lorensen wrote:
>>
>> Jesse,
>>
>> I loaded your data into paraview (paraview.org), applied the
>> Delaunay2D filter->ContourFilter and produced the attached image. Is
>> this what you would expect?
>>
>> Bill
>>
>>
>> On Mon, Dec 7, 2009 at 1:55 PM, Jesse Kim <jinryongkim at gmail.com> wrote:
>>
>>>
>>> Hi Bill and David,
>>>
>>> Thanks for the reply.
>>> For the clarification, let me provide my sample data set. What I would
>>> like
>>> to do here is to do the interpolations among these scalar values
>>> associated
>>> with some geographical locations (75 locations) so that I can have smooth
>>> iso-contour or iso-surface. This the dataset of some geographical
>>> locations
>>> (75 locations) and their scalar values.
>>>
>>> # vtk DataFile Version 2.0
>>> Weather observing stations
>>> ASCII
>>> DATASET POLYDATA
>>> POINTS 75 float
>>> 660.905194 527.736720 0.0
>>> 536.263098 683.230547 0.0
>>> 702.452710 1112.016367 0.0
>>> 710.006701 838.724374 0.0
>>> 354.965505 414.650300 0.0
>>> 660.905194 862.283951 0.0
>>> 694.898493 485.329312 0.0
>>> 657.128312 612.551535 0.0
>>> 589.141714 975.370370 0.0
>>> 490.938700 424.074074 0.0
>>> 260.539826 640.823140 0.0
>>> 317.195324 805.740741 0.0
>>> 260.539826 376.954638 0.0
>>> 366.296604 164.917601 0.0
>>> 113.235531 75.391041 0.0
>>> 128.343513 98.950617 0.0
>>> 664.682303 720.925926 0.0
>>> 653.351203 932.962963 0.0
>>> 358.742613 735.061728 0.0
>>> 173.667911 329.835485 0.0
>>> 158.559929 1107.3046210 0.0
>>> 498.492917 1088.4567900 0.0
>>> 294.533125 546.584268 0.0
>>> 524.931999 588.991675 0.0
>>> 589.141714 466.481481 0.0
>>> 524.931999 245.020670 0.0
>>> 181.222129 1088.4567900 0.0
>>> 256.762717 160.205856 0.0
>>> 585.364606 890.555556 0.0
>>> 407.844121 574.855873 0.0
>>> 528.709108 164.917601 0.0
>>> 430.506320 782.181164 0.0
>>> 385.181921 862.283951 0.0
>>> 608.026805 292.139823 0.0
>>> 547.594198 815.164515 0.0
>>> 370.073713 480.617284 0.0
>>> 298.310007 862.283951 0.0
>>> 41.471825 65.966984 0.0
>>> 604.249696 711.502152 0.0
>>> 162.336811 65.966984 0.0
>>> 460.722510 669.094744 0.0
>>> 562.702406 367.530864 0.0
>>> 347.411514 334.547231 0.0
>>> 362.519722 240.308642 0.0
>>> 132.120621 669.094744 0.0
>>> 177.445020 226.172840 0.0
>>> 396.513021 1027.2015520 0.0
>>> 67.911133 131.934251 0.0
>>> 113.235531 183.765432 0.0
>>> 211.438319 914.115132 0.0
>>> 725.114910 617.263280 0.0
>>> 422.952102 951.810794 0.0
>>> 192.553228 584.279930 0.0
>>> 596.695705 537.160494 0.0
>>> 728.891792 758.621305 0.0
>>> 453.168519 259.156473 0.0
>>> 521.155117 278.004021 0.0
>>> 475.830718 362.818836 0.0
>>> 517.378008 518.312663 0.0
>>> 290.756016 273.292275 0.0
>>> 396.513021 1130.864198 0.0
>>> 298.310007 70.679012 0.0
>>> 154.782821 499.465115 0.0
>>> 237.877627 1079.033016 0.0
>>> 679.790511 296.851852 0.0
>>> 135.897730 292.139823 0.0
>>> 513.600899 871.707725 0.0
>>> 502.269800 998.929947 0.0
>>> 215.215427 259.156473 0.0
>>> 260.539826 768.045362 0.0
>>> 245.431617 786.892910 0.0
>>> 218.992309 989.506173 0.0
>>> 392.735912 650.246914 0.0
>>> 324.749315 310.987654 0.0
>>> 339.857523 942.386737 0.0
>>> POINT_DATA 75
>>> SCALARS req_prep_0 float
>>> LOOKUP_TABLE default
>>> 184.949631
>>> 125.071189
>>> 114.655333
>>> 142.508891
>>> 250.255094
>>> 132.980147
>>> 132.369983
>>> 104.52796
>>> 331.737495
>>> 336.049583
>>> 214.249765
>>> 117.033152
>>> 329.449907
>>> 266.396892
>>> 147.324093
>>> 293.163118
>>> 104.33426
>>> 313.719804
>>> 207.564979
>>> 109.947172
>>> 143.08005
>>> 143.859373
>>> 189.977409
>>> 126.483623
>>> 217.989847
>>> 372.728658
>>> 343.744282
>>> 94.816421
>>> 187.774541
>>> 186.499795
>>> 337.102472
>>> 182.862572
>>> 125.000005
>>> 520.225266
>>> 267.150263
>>> 104.699336
>>> 187.176938
>>> 111.811702
>>> 314.11783
>>> 463.261076
>>> 131.671659
>>> 361.803069
>>> 272.000024
>>> 178.927209
>>> 274.940403
>>> 176.914528
>>> 249.996726
>>> 225.34729
>>> 220.164636
>>> 192.443055
>>> 274.59666
>>> 242.720081
>>> 163.316313
>>> 214.000012
>>> 150.596283
>>> 274.416211
>>> 532.135911
>>> 453.662097
>>> 229.363398
>>> 733.273974
>>> 151.398179
>>> 162.908337
>>> 244.352757
>>> 332.847796
>>> 480.445379
>>> 541.82268
>>> 384.111595
>>> 201.312356
>>> 234.118599
>>> 185.278497
>>> 159.692496
>>> 281.602642
>>> 356.659038
>>> 377.949511
>>> 469.000015
>>>
>>> Bill Lorensen wrote:
>>>
>>>>
>>>> The data for the example should be some points scattered in space. I
>>>> assume that is what Jin has, not just three points on a line. I'll dig
>>>> up some meaningful data, uless Jin can share a small sample of his
>>>> data.
>>>>
>>>> Bill
>>>>
>>>> Bill
>>>>
>>>> On Mon, Dec 7, 2009 at 1:11 PM, David Doria <daviddoria+vtk at gmail.com>
>>>> wrote:
>>>>
>>>>
>>>>>
>>>>> On Mon, Dec 7, 2009 at 12:20 PM, David Gobbi <david.gobbi at gmail.com>
>>>>> wrote:
>>>>>
>>>>>
>>>>>>
>>>>>> On Mon, Dec 7, 2009 at 9:51 AM, David Doria <daviddoria+vtk at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> On Mon, Dec 7, 2009 at 11:43 AM, Jin Ryong Kim
>>>>>>> <jinryongkim at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>> I have a question about interpolation method in VTK.
>>>>>>>> Currently, I'm trying to interpolate scalar values between data
>>>>>>>> points
>>>>>>>> to
>>>>>>>> create a contour map.
>>>>>>>> I have some data points set (x, y, z) and scalar values related with
>>>>>>>> each
>>>>>>>> data point.
>>>>>>>> So far, I found out vtkProbeFilter but when I tried, nothing came
>>>>>>>> up.
>>>>>>>> My questions are as follow.
>>>>>>>> 1. Is vtkProbeFilter the right choice in this case?
>>>>>>>> 2. If not, what are the right vtk classes to accomplish such a goal?
>>>>>>>> If anyone has the solution for this, please let me know.
>>>>>>>> Thanks in advance!
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>> Jin,
>>>>>>>
>>>>>>> If I'm not mistaken you sent this same question yesterday. I am
>>>>>>> interesting in making an example of this so I have started poking
>>>>>>> around. I understand that you may be in a hurry, but asking twice is
>>>>>>> just going to annoy people on the list, making your answer come
>>>>>>> slower, not faster.
>>>>>>>
>>>>>>> Can anyone confirm or deny that ProbeFilter is the right way to go?
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> The probe needs cells to interpolate the data.  If all you have is
>>>>>> points, then you have to apply delaunay first to make the cells, and
>>>>>> then use probe to interpolate the data onto a grid (i.e. make an
>>>>>> image), and then contour the grid.  It might also be possible to
>>>>>> contour directly from the output of delaunay, but I'm not sure whether
>>>>>> VTK can do that.  I'm no expert in this area, but hopefully I've
>>>>>> answered your question.
>>>>>>
>>>>>>  David
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>> From Bill's suggestion I have tried to make an example:
>>>>> http://www.vtk.org/Wiki/VTK_Examples_Interpolation
>>>>>
>>>>> the problem is that the Shepard filter outputs an ImageData and the
>>>>> ContourFilter seems to expect a DataObject.
>>>>>
>>>>> Jin, this is a simple version of what you are trying to do, correct?
>>>>> If so, let try to get this little demo working.
>>>>>
>>>>> Thanks,
>>>>>
>>>>> David
>>>>> _______________________________________________
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>>>>>
>>>>>
>>>>>
>>>>
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>>>>
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
>
>