[vtkusers] Problem getting correct results with vtkProjectedTerrainPath

[Elvis Dowson]

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

-------------- next part --------------
A non-text attachment was scrubbed...
Name: Problem with vtkWrapScalar scale setting 01.jpg
Type: image/jpeg
Size: 36692 bytes
Desc: not available
URL: <http://www.vtk.org/pipermail/vtkusers/attachments/20081110/1efece59/attachment.jpg>
-------------- next part --------------


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