SUCHW - Change Header Word using one or two header word fields

suchw <stdin >stdout [optional parameters]

Required parameters:
none

Optional parameters:
key1=cdp,... output key(s)
key2=cdp,... input key(s)
key3=cdp,... input key(s)
a=0,... overall shift(s)
b=1,... scale(s) on first input key(s)
c=0,... scale on second input key(s)
d=1,... overall scale(s)

The value of header word key1 is computed from the values of
key2 and key3 by:

val(key1) = (a + b * val(key2) + c * val(key3)) / d

Examples:
Shift cdp numbers by -1:
suchw <data >outdata a=-1

Add 1000 to tracr value:
suchw key1=tracr key2=tracr a=1000 <infile >outfile

We set the receiver point (gx) field by summing the offset
and shot point (sx) fields and then we set the cdp field by
averaging the sx and gx fields (we choose to use the actual
locations for the cdp fields instead of the conventional
1, 2, 3, ... enumeration):

suchw <indata key1=gx key2=offset key3=sx b=1 c=1 |
suchw key1=cdp key2=gx key3=sx b=1 c=1 d=2 >outdata

Do both operations in one call:

suchw<indata key1=gx,cdp key2=offset,gx key3=sx,sx b=1,1 c=1,1 d=1,2 >outdata


Credits:
SEP: Einar Kjartansson
CWP: Jack K. Cohen
CWP: John Stockwell, 7 July 1995, added array of keys feature
Delphi: Alexander Koek, 6 November 1995, changed calculation so
headers of different types can be expressed in each other