DDS supports the SEG (Society of Exploration Geophysicists) SEG-Y format as "segy". The effective default attributes for segy output is:
format= segy float 4 ibm ebcdic no_green_prefix no_green_suffix
Examples of attributes available for segy (see Attributes) include the following:
Attributes Description --------------- --------------------------------- no_green_prefix no green word prefix no_green_suffix no green word suffix green_prefix 4|8 green word prefix size green_suffix 4|8 green word suffix size integer 1|2|4|8 integer samples size float 4|8 ibm|ieee[x] float samples type & size hdrswap binary and trace headers "Little Endian" ascii card header text is ascii format ebcdic card header text is ebcdic format charisma charisma format TrcNumSmp handle variable trace lengths
Other effective segy defaults include:
axis= t x y sort.x=CdpTrcNum sort.y=FieldRecNum
DDS automatically detects the segy format and attributes of input binary data. If they conflict with attributes explicitly defined by format, a warning is issued and the override is honored. Output data attributes take predefined defaults, unless explicitly overridden.
The segy seismic format is described by three major types,
SEGY_CARD (PREAMBLE), SEGY_BINARY (PREAMBLE2), and
SEGY_TRACE (SEQUENCE). This format is created using
the "${DDSROOT}/segy.fmt.dds
" Dictionary.
"${DDSROOT}/segy.map.dds
" provides default mapping
Definitions. Either of these can be copied into some other
directory and edited to modify the format. Point DDS to this
directory with DDS_PATH.