[OpendTect_Developers] I want to ask a question about cbvs

[Bert Bril]

Hi,


chaisheng wrote:

> I would know about the cbvs format ,can you give me some document about
> cbvs ?

You'd better not learn about it. You want to access it through 
interfaces. You wouldn't consider accessing JPEG or PNG directly either, 
right? CBVS is messy, no doc available except a few lines of comments in 
the source files.

CBVS stands for Common Basic Volume Storage. At the time, I thought we 
would have many different volume storage needs, and this would be the 
common format for those. It turns out we only use it for seismics.

We are not very happy with CBVS, because it lacks all sorts of modern 
goodies like compression, bricking, parallel access, and so forth. We're 
always thinking about replacing the format with something else, but the 
project would be big and the need is still not big enough.


What to use?

For write - always deliver data per trace.
* Inline-sorted traces or 2D: SeisTrcWriter (seiswrite.h)
* Single traces, unknown sorting (but sorted!): SeisImporter 
(seisimporter.h)
* Mostly sorted traces, that may arrive out-of-order (for MT pruposes): 
SeisSequentialWriter (seiswrite.h)


For reading - you can always declare your 'interest' by providing a 
Seis::SelData object (seisselection[impl].h).

* One trace at a time: SeisTrcReader (seisread.h). Random access via 
'goTo()'.
* Moving subcubes (the object buffers what's necessary for you): 
SeisMSCProvider (seismscprov.h)


Read and write:
* Trace-by-trace: SeisSingleTraceProc (seissingtrcproc.h). Allows 
separate exclusion of traces, and doing your own processing - via CallBacks.

* Fully MT, all shapes, processes - basically geometry uncoupled from 
data access: the Attribute Engine. An example of attribute programming 
is in:
http://opendtect.org/rel/doc/Programmer/plugins.htmltutattrib




/Bert

-- 
-- Bert Bril / OpendTect developer at dGB
-- mailto:Bert.Bril at opendtect.org , http://opendtect.org