I'm having Difficulty Using my Favorite Data Loader

The Perl Script a2e.pl to Massage the Proposed EnCana SEGY Standard
The perl script a2e.pl exists to get around some awkward steps when attempting to use the following products to load the Proposed EnCana SEGY standards. There appear to be two problems with our current data loaders, one with reading the Descriptive Header as ASCII and the other in reading a format number greater than three. This simple fix is to fix the data (temporarily at least) back to EBCDIC and change the format number to 1.

The a2e script will automatically detect if each 80 column line of the descriptive (textual) header is ASCII or EBCDIC and will overwrite the header with EBCDIC if it's in ASCII.

To the right we have a Textual header that has been converted to EBCDIC. The only problem I observe is that it appears the dashes and underscores have been reversed.
Panther's SDL seems to explode when it attempts to view the EBCDIC header written as ASCII. It seems that all of these loaders have problems with knowing what to do with a format code greater that the number 3. To get Paradigm to work, you have to manually overide the format code to 1 to get the loader to properly read the data!

This script will change any format code (binary header bytes 25, 26) to the number 1. You MUST then tell your loader that the data are IEEE 32 BIT FLOATING point. (Look at the histogram display). Here's how to run the script: 

ls *sgy > junk
 ~ekeyser/Perl/a2e.pl

#############################################################
File Name = test.A43558.01KUG03.f-pr-fk-fx-mig.042003.gox.sgy has been found 
#############################################################
C 1 CLIENT: ENCANA______..__          PROCESSED BY:GEO-X SYSTEMS LTD. 2003Apr04
C 2 LINE: 03KUG03          REFERENCE ID: 43558    AREA: KUGMALLIT              
C 3 STACK TYPE: FILTERED PRE-STACK FK+POST STACK FX+MIGR                       
C 4  SHOT FOR:                AEC WEST                                         
C 5  SHOT BY:                 WESTERN GECO.         PTY: 1261                  
C 6  DATE:                    MAY 2001                                         
C 7  LOCATION:                KUGMALLIT  107-E-8                               
C 8  DIRECTION:               SP. 709.5  ---> SE   SP. 181.5                   
C 9  SPREAD:                  4485 - 15 * 15 - 4485 M                          
C10  SOURCE INTERVAL:         120 M            RECEIVER INTERVAL: 30 M         
C11  ACQUISITION FOLD:        3750 %                                           
C12  SOURCE: DYNAMITE         1 X 20 KG @ 18 M DEPTH,                          
C13  RECEIVERS:               OYO 30CT 10 HZ; 70% DAMPING; 6 OVER 2 M          
C14  INSTRUMENTS:             SERCEL 408       300 TRACE                       
C15  GAIN MODE:                                TAPE FORMAT: SEG-D              
C16  FIELD FILTERS:           .8 NYQ MIN.      NOTCH: OUT                      
C17  SAMPLE INTERVAL:         2 MS             RL: 3.0 S                       
C18                                                                            
C19 DATUM ELEV 200   M   REPL VEL 3500 M/SEC   TIME OF FIRST SAMPLE 0    MS    
C20 PROJECTION:  UTM ZONE 8      SURVEY DATUM: NAD 27_?                        
C21 PROCESSING: DEMULTIPLEX (OR REFORMAT) AND AMPLITUDE RECOVERY               
C22 PROCESSING: PHASE COMPENSATION...SYSTEM MINIMUM-PHASE CONVERSION           
C23 PROCESSING: 5-COMP SUR CONSIST SIG DCON... Time-variant spectral whiten    
C24 PROCESSING:  DESIGN WINDOW: AT 15 M, 300- 3000 MS; AT 4485 M, 1300- 3000 MS
C25 PROCESSING: FK on Shot Records +/- 7 ms/trace dip rejection                
C26 PROCESSING: STATICS...ELEVATION/WEATHERING, REFRACTION ANALYSIS            
C27 PROCESSING: TRACE EDITING, TIME-VARIANT MEAN SCALING                       
C28 PROCESSING: NMO CORRECTION (VEL. ANALYSIS: 10 CDPS EVERY 30   CDPS)        
C29 PROCESSING: FIRST BR. MUTE (X/T) 400/700 ; 1990/1800-1810 ; 4420/2800 (M/MS
C30 PROCESSING: SURFACE CONS. RES. STATICS (WIND 500 -3000 MS, MAX +/-24 MS)   
C31 PROCESSING: TRACE GATHER  (MAX FOLD 43 )                                   
C32 PROCESSING: CROSS-CORRELATION STATICS (WIND 500 -3000 MS, STAT +/- 6  MS)  
C33 PROCESSING: STACK                                                          
C34 FX NOISE REDUCTION                                                         
C35 FINITE DIFFERENCE  MIGRATION (100% STACKING VELOCITIES)                    
C36 FILTER:  ORMSBY FILTER    8 /12-70 /85  HZ                                 
C37 SCALING: MEAN WINDOW 100 -3000 MS                                          
C38 TRACE HDR: BYTES 17-20 SP, 21-24 CDP, 81-84 UTM EAST, 85-88 UTM NORTH.     
C39                                                                            
C40                                                                            
Format 6 changed to format 1
fini --
Note that all non blank lines will be displayed in ASCII to the screen and format codes greater than three will be changed to one. If it doesn't work, check that you have file write permissions. They are needed to correct the file. Make a copy for the first time and if you don't trust the program.
Copyright © 2003 -
Site Owner: Eric Keyser
Last Updated: Feb 20, 2004