[vtkusers] How to import NASA SRTM DEM data into VTK

[Elvis Dowson]

Hi Matieu,
  			When I set the data extent as follows:

  reader SetDataExtent 0 1200 0 1200 0 0

I get the following error.

File operation failed. row = 600, Read = 4804, FilePos = -1

The image is partially reconstructed, with a really big black border  
around, with a central white patch, with some faint traces of some  
sort of relief shading.

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What could be wrong and causing this read error?

Best regards,

Elvis Dowson


On Oct 13, 2008, at 5:38 PM, Mathieu Malaterre wrote:

> On Mon, Oct 13, 2008 at 3:32 PM, Michael Jackson
> <mike.jackson at bluequartz.net> wrote:
>> http://www.vtk.org/doc/release/5.2/html/a00665.html#b853fba8decf9550e4678fa4f4ca9ad0
>>
>> Page 405 in the 4th edition of the "Visualization Toolkit" explains  
>> what the
>> data extents are.
>>
>> Basically they are the min/max (in x,y,z) of your data. For example  
>> if your
>> data was 100x 50 x10 but the actual minimum value was 1000, 1000,  
>> 1000 (x,
>> y, z) then your data extents would be 1000, 1101, 1000, 1051, 1000,  
>> 1011
>> (Xmin, Xmax, Ymin, Ymax, Zmin, Zmax).
>
> As I said in my previous email, if your data is 512x512x1, VTK
> dimension is (512, 512, 1) BUT data extent is: (0, 511, 0, 511, 0, 0)
>
> Elvis,
>
> you are off by one, AFAIK.
>
> reader SetDataExtent 0 1200 0 1200 0 0
>
> 2cts
> -- 
> Mathieu