Topic:
How to reverse the current trace polarity using the IES INVERT function.

Description:
The IES INVERT function will invert the seimic trace.  Postive amplitudes become
negative and negative amplutudes become positive.

Solution:
INVERT is a "logical operator with values for YES and NO.


To utilize INVERT you must first set sp to use an expression then write
a FORTRAN if statement.

SP = SP; if (CDP .EQ. 17); THEN; INVERT = YES; ENDIF
Only traces where CDP is 17 will be inverted.

SP =SP; if (SP .LT. 200); THEN; INVERT = YES; ENDIF
Only traces where SP is lses than 200 will be inverted.



Last Modified on: 28-SEP-00