[OpendTect_Users] strategies for dealing with large cubes

[Colin Hawke]

Dear Vikram,

If your data is at 32bit you can convert to 16bit or even 8bit. Because of the reduction in dynamic range 8bit is really only good for structural work. 16bit is a good compromise as it still has a reasonable dynamic range and still gives you a halving of disk space. Remember you'll need to scale your data first (8bit = -127 to +127 and 16bit -32767 to +32767). 

It would be nice if you could get the statistics of the volumes such as min and max amplitude so you can do this scaling easily. I export as SEGY and then scan the cube with the SEGY input utilities in OpendTect - this even gives you the scalars you need to do the conversion to different bit ranges; perhaps there is an easier method? 

It would also be nice if the standard deviation of the sample amplitudes were also reported so that a Z-Score transform can be applied (used for equalizing multiple volumes in AVO or time-lapse work) ...

Renee: When you use the 'copy cube' option to sub-sample in time does it apply a 3/4 Nyquist anti-alias filter or similar? 

Cheers

Colin

Date: Fri, 6 May 2011 11:19:56 -0500
From: renee.bourque at dgbes.com
To: users at opendtect.org
Subject: Re: [OpendTect_Users] strategies for dealing with large cubes

Dear Vikram, 
Yes, this can be done by opening the manage seismic window, select your volume, select "copy cube". In the copy cube window you will have a "volume subselection" option. In there you can adjust your inline/crossline/time steps. The larger the steps, the smaller the output volume. 

Regards,Renee Bourque


-- 
S. Renee Bourque
Geoscientist dGB Earth Sciences1 Sugar Creek Center Blvd., Suite 935
Sugar Land, TX 77478Tel: +1 281 240 6910, Fax: +1 281 240 3944
email: renee.bourque at dgbes.comskype: dgbrenee





On Fri, May 6, 2011 at 8:12 AM, Vikram Unnithan <v.unnithan at jacobs-university.de> wrote:




  

    
  
  
    Dear All,

      Are there any recommendations for dealing with large datasets (3d
      cube 14GB)? I would like to subsample this so that I can test out
      various options before using the full resolution. I probably have
      overlooked the option/method/button and hence a rather trivial
      question, how should or could one subsample in opendect. Any
      pointers would be appreciated,

      regards

      Vikram

      

    
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