[vtkusers] Problem getting correct results with vtkProjectedTerrainPath
Elvis Dowson
elvis.dowson at mac.com
Mon Nov 10 01:09:59 EST 2008
Hi Mike,
You're right. I was using the non-scaled DEM data.
Mike, why do these DEM reconstructions look so spiky? If you recall
the reconstruction of the NASA SRTM dataset, I get some really un-
natural and spiky looking settings as shown in the attached image. So
the question is, which one is the correct one from a geo-referencing
stand-point?
reader SetFileName "N46W123.hgt" ;# Mount St. Helens
warp SetScaleFactor 1.0
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Best regards,
Elvis
On Nov 10, 2008, at 5:27 AM, Michael Jackson wrote:
> MY guess on this one is that the vtkProjectedTerrainPath is using
> the original (non-scaled) DEM data where as the image data is being
> warped to 10% of the original height, in other words, you are really
> working from 2 different data sets: a scaled and the original.
>
> You need to somehow pass the scaled (warped) data to the
> vtkProjectedTerrainPath filter. If this is not possible you may want
> to consider actually scaling the data yourself to 10% of its value.
> In C++ I would get the pointer to the 0 index, and then multiply the
> z value by 0.10. This probably isn't a "best practice" method but
> would solve the problem.
> _________________________________________________________
> Mike Jackson mike.jackson at bluequartz.net
> BlueQuartz Software www.bluequartz.net
> Principal Software Engineer Dayton, Ohio
>
> On Nov 9, 2008, at 4:09 PM, Elvis Dowson wrote:
>
>> Hi,
>> If I set the vtkWrapScalar scale factor to 1, then I see
>> that the projected terrain path closely follows the 3D terrain.
>> However, the image data is greatly exaggerated.
>>
>> <Problem with vtkProjectedTerrainPath 02.jpg>
>>
>> How can I get vtkProjectedPath to follow the reconstructed terrain
>> created with a wrap scaler factor of 0.1?
>>
>> Best regards,
>>
>> Elvis Dowson
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