segy2usp

NAME

SYNOPSIS

DESCRIPTION

segy2usp : This routine it designed to simplify the conversion of SEGY data into the USP format. A three-level system of header mapping input is used to determine the source of the output datasets header information. First off, the startup script sets a SEGY2USP_DEFAULT_MAPPING variable which specifies where to get a standard set of default mappings for common output information. These values are used if no other is specified for each particular mnemonic via the -M or -map specifications which are controlled by the user. Any file containing a set of mappings input by specifying the -M argument is read in next and entries which have a destinamtion field (ie. before the '=' character) matching an earlier entry in the defaults will now take precedence. Similarly, mappings specified on the command line with the -map argument take the highest precedence of all. See the section on MAPPINGS below for a discussion of the format for these specifications.

segy2usp gets both its data and its parameters from command line arguments. These arguments specify the input, output, trace header mappings, and verbose printout, if desired.  

Command line arguments

-N ntap [default: stdin]

Enter the input data set name or file immediately after typing -N unless the input is from a pipe in which case the -N entry must be omitted. This input file should include the complete path name if the file resides in a different directory. Example -N/b/vsp/dummy tells the program to look for file 'dummy' in directory '/b/vsp'.

-O otap [default: stdout]

Enter the output data set name or file immediately after typing -O. This output file is not required when piping the output to another process. The output data set also requires the full path name (see above).

-M mapping_file [default: none]

File containing a set of header mappings. Format is discussed below.

-map map_specification [default: none]

Specifies source out output header information. Format is discussed below. Multiple instances of the -map argument may be specified.

-native line | trace | data | all [default: none]

Specifies that one particular portion of the input SEGY data is in native format for this particular architecture and is not to be byte swapped. Currently, the only architectures on which this will have an effect is little-endian machines. Up to three -native arguments may be specified. The line, trace, and data flags refer to the line header, trace header, and trace data on the input dataset. If -native is passed with no arguments, all is implied and no byte swapping will occur. [default: off]

-V verbosity

Enter the command line argument '-V' to get additional printout. A more verbose printout may be specified by entering a verbosity value of 2. [default: off]

-? or -h

Enter the command line argument '-?' or -h to get online help. The program terminates after the help screen is printed.

MAPPINGS

usp_header_mnemonic=[segy_header_mnemonic|constant]

For instance, to get the USP record and trace numbers from the SEGY field trace record and trace numbers, the definitions would look like:

RecNum=FieldRecNum
TrcNum=FieldTrcNum

and to specify the number of records in the line header of the output dataset to a known value such as 500, a similar definition

NumRec=500

would be used.

The mnemonic values used for both USP and SEGY data formats may be obtained by running the program hdrdesc. A complete description of the formats, including the mnemonics used and a brief description of each field will be produced.

BUGS

SEE ALSO

AUTHOR

COPYRIGHT

Index

NAME

SYNOPSIS

DESCRIPTION

Command line arguments

MAPPINGS

BUGS

SEE ALSO

AUTHOR

COPYRIGHT