IV. FormatsI. asp

By creating new "fmt:" structure Definitions, a new data format can be created. DDS has a built-in generic format called "asp" (Amoco Seismic Processing). It has flexible Trace Headers (see Fmt Control for more detauls). There are no format attributes and it is specified by:

format= asp

Whenever converting to asp from another format, all the incoming Trace Headers are kept in their original data types. The only exception to this is when coming from a segy (or segy1) format, usp Trace Headers are created and mapped similarly to usp; and when going to segy (or segy1) format, the Trace Headers are mapped to segy (or segy1) header names much like coming from usp. This makes it easier with most application programs so many of the standard headers (eg. SrPtXC RcPtYC) are in a more standard header name.

New Trace Header names can be (re)created "on the fly" with the use of the "MOD_FIELD" Definition documented in the Fmt Control section.

There are serveral other formats defined that are a subset of the asp format (other than sep described earlier). These are all some form of a "cube" dataset that do not have Trace Headers -- Samples only; and as such they are all regularized on the hypercube dimensions.

Format   Trace Header  Data Type†
------   ------------  ----------------------------------
cube     CUBE_TRACE    any type as defined by SAMPLE_TYPE
fcube    FCUBE_TRACE   float4
fcubex   FCUBEX_TRACE  float4x (Little Endian order)
dcube    DCUBE_TRACE   float8
dcubex   DCUBEX_TRACE  float8x
ccube    CCUBE_TRACE   complex8
ccubex   CCUBEX_TRACE  complex8x
icube    ICUBE_TRACE   integer4
icubex   ICUBEX_TRACE  integer4x
i2cube   I2CUBE_TRACE  integer2
i2cubex  I2CUBEX_TRACE integer2x
i1cube   I1CUBE_TRACE  integer1
    

DDS cannot automatically detect these non-standard formats and therefore requires a DDS Dictionary along with the binary data. Each of these generic formats are defined by their Trace Headers in the "${DDSROOT}/asp.fmt.dds" Dictionary. Several default header mapping defintions for asp are provided in "${DDSROOT}/asp.map.dds".

^† See Data Types for more details.