bridge FAQ



The following are Frequently Asked Questions concerning the DDS Revision Level 3 version of bridge.

If you would like to contribute to this FAQ, please send mail to pgarossino@freeusp.org.

Last updated December 8, 2005


Questions

The Basics

Scanning SEGY Headers

SEGY EBCDIC/ASCII Header Editting

SEGY and Magnetic Tape Devices

SEGY and 3rd Party Software

Header Mapping

Header Arithmetic

Trace Padding

Handling SEGY Format Variations


Answers

1.1 HOW DO I RUN BRIDGE?


1.2 WHY IS THE COMMAND LINE SYNTAX SO NON-USP?


1.3 HOW DO I GET MAN PAGE INFORMATION?


2.0 HOW CAN I SCAN MY SEGY TRACE HEADER ENTRIES?


2.1 HOW CAN I SCAN MY SEGY EBCDIC/ASCII HEADER ENTRIES?


2.2 WHERE CAN I GET A SEG-Y FORMAT DESCRIPTION


2.3 Can bridge deal with SEG-Y Classic and the SEG-Y Revision 1 formats?


3.0 HOW CAN I UPDATE MY SEGY EBCDIC/ASCII HEADER ENTRIES?


4.0 HOW DO I HANDLE SEGY TAPE INPUT?


4.1 HOW DO I HANDLE SEGY TAPE OUTPUT?


4.2 HOW DO I READ A MULTI-TAPE SEGY DATASET?


4.3 HOW DO I CREATE A MULTI-TAPE SEGY DATASET?


4.4 HOW DO I READ MULTIPLE SEGY DATASETS FROM A SINGLE TAPE?


4.5 CAN I READ MULTI-TAPE DATASETS FROM MORE THAT 1 TAPE DRIVE?


4.6 CAN BRIDGE HANDLE 3480 CARTRIDGES?


5.0 WHAT DO I HAVE TO DO TO CREATE A DATASET READABLE BY LANDMARK?


5.1 WHAT DO I HAVE TO DO TO CREATE A DATASET READABLE BY PROMAX?


5.2 WHAT DO I HAVE TO DO TO CREATE A DATASET READABLE BY GEOQUEST?


6.0 HOW DO I DO TRACE HEADER MAPPING BETWEEN SEGY AND USP?


6.1 HOW DO I DO LINE HEADER MAPPING BETWEEN SEGY AND USP?


6.2 HOW DO I ACCESS BYTES 181 - 240 IN THE SEGY TRACE HEADER?


6.3 HOW DO I PUT DATA INTO BYTES 181 - 240 IN THE SEGY TRACE HEADER?


6.4 HOW CAN I MAP INTO TVPTnn AND TVPVnn ENTRIES IN THE USP TRACE HEADER?


7.0 CAN I DO HEADER ARITHMETIC?


7.1 CAN I DO HEADER ARITHMETIC ON USP DATA?


8.0 HOW DO I DO USP TRACE PADDING WHEN READING SEGY DATA?


8.1 CAN I GET USP TRACE PADDING BASED ON TrcNum AND HAVE RecNum BE ASSIGNED SEQUENTIAL?


8.2 CAN I WRITE A SEGY DATASET WITHOUT DEAD TRACES?


9.0 HOW CAN I HANDLE NON-STANDARD SEGY TRACE HEADER FORMATS?


9.1 HOW CAN I HANDLE AUXILLARY TRACES, FOR INSTANCE DROPPING THEM ON THE WAY IN FROM SEGY TO USP?


9.2 My SEGY reel header lies about the number of samples per trace. How can I reassign that value so that I can read the data from tape at all?


9.3 How can I create SEGY data in IEEE floating point format instead of the standard IBM Floating point?