NAME
horzn_limit - read workstation event file and output only
those entries within input survey limits
SYNOPSIS
horzn_limit [ -Nntap ] [ -Ootap ] [ [ -diminmindi ] [
-dimaxmaxdi ] [ -liminminli ] [ -limaxmaxli ] ] [ -x1x1 ] [
-y1y1 ] [ -x2x2 ] [ -y2y2 ] [ -x3x3 ] [ -y3y3 ] [ -x4x4 ] [
-y4y4 ] [ -cldmcldm ] [ -ildmildm ] [ -f2m ] [ -m2f ] [ -V ]
[ -? ]
DESCRIPTION
horzn_limit takes an input iterpretive workstation horizon
file and essentially limits the entries to only those fal-
ling within the user supplied survey limits. These entries
are output in exactly the same format as the input. The main
reason for running this is if you are interested in only a
small portion of a larger survey. The horizon file from a
large survey may contain millions of entries of which you
may be interested in a few thousand. Running an application
like tim2hed3d to put these event times into the trace
headers of the data may require a considerable amount of
time just to read in such a large file especially if you are
working on individual lines and having to do this repeat-
edly. It is much faster for tim2hed3d to read a small file.
horzn_limit gets both its data and its parameters from com-
mand line arguments. These arguments specify the input and
output horizon files, survey corner locations, LI & DI lim-
its, and verbose printout, if desired.
Command line arguments
-N ntap
Enter the name of the input workstation event file.
Currently the file must be 5 column format: records,
traces (or the reverse), X, Y, time or depth. The XYs
must be in the same coordinate system as the input
seismic data. The main reason for running this is if
you are interested in only a small portion of a larger
survey. The horizon file from a large survey may con-
tain millions of entries of which you may be interested
in a few thousand. Running an application like
tim2hed3d to put these event times into the trace
headers of the data may require a considerable amount
of time just to read in such a large file especially if
you are working on individual lines and having to do
this repeatedly. It is much faster for tim2hed3d to
read a small file. Default is stdin.
-O otap
Enter the name of the output workstation event file.
Currently the output file will be exactly the same
format as the input. Default is stdout.
x4, y4]
-x1, -y1, -x2, -y2, -x3, -y3, -x4, -
y4 [x1, y1, x2, y2, x3, y3,
Enter the area of interest over the survey with the X-Y
coordinates (ft,m) defining the four corners of a
parallelogram on the ground. Corner 1 is always
defined to be the northeast corner. Going either clock-
wise or counter clockwise (clockwise recommended) from
Corner 1 the first move to Corner 2 should be in the
direction of a receiver or shot line. The origin will
always be defined to be the lower left (corner 3) of
the survey. The values must be the same units as those
given in the source, receiver, and midpoint X-Ys in the
trace headers.
-cldm cldm
Enter the crossline (along X or side 2-3) cell dimen-
sion (ft,m). For most shooting geometries this will be
1/2 the line or group spacing depending on the orienta-
tion of side 2-3 with respect to the receiver lines.
The sides are defined to be X along side 1-4 (roughly
cross-line direction), Y along side 1-2 (roughly in-
line direction). Remember when setting up the coordi-
nate system the line joining Corner (1) to Corner (2)
should be in the direction of a receiver or shot line.
No default.
-ildm ildm
Enter the inline (along Y or side 1-2) cell dimension
(ft,m). For most recording geometries this will be 1/2
the line or group spacing depending on the orientation
of side 1-2 with respect to the receiver lines. The
sides are defined to be X along side 1-4 (roughly
cross-line direction), Y along side 1-2 (roughly in-
line direction). Remember when setting up the coordi-
nate system the line joining Corner (1) to Corner (2)
should be in the direction of a receiver or shot line.
No default.
-limin, limax minli, maxli
Enter the minimum and maximum line indexes to output.
The output survey will have so many bins in the inline
direction and so many bins in the crossline direction.
This is a handy way to start and end outputting bins at
specified sequential inline numbers. Default is the
first and last inline bin as determined from the 4
corners of the survey provided on the command line..
-dimin, dimax mindi, maxdi
Enter the minimum and maximum crossline indexes to
output. The output survey will have so many bins in the
inline direction and so many bins in the crossline
direction. This is a handy way to start and end output-
ting bins at specified sequential crossline numbers.
Default is the first and last crossline bin as deter-
mined from the 4 corners of the survey provided on the
command line..
-f2m Enter the command line argument '-f2m' to scale the
workstation event XYs from feet to meters. This will
have no effect on the output XYs. The default is no
scaling.
-m2f Enter the command line argument '-m2f' to scale the
workstation event XYs from meters to feet. This will
have no effect on the output XYs. The default is no
scaling.
-V Enter the command line argument '-V' to get additional
printout.
-? Enter the command line argument '-?' to get online
help. The program terminates after the help screen is
printed.
BUGS
Currently only the 5-column Landmark format is handled. But
awk can be used with most other files to jury rig an accept-
able format.
EXAMPLE
horzn_limit -Nin_event -Oout_event -x13000 -y12000 -x20
-y23000 \
-y30 -x43000 -y40 -ildm50 -cldm100 -f2m
where the the X-axis corresponds to the receiver lines and
we go counter clockwise starting from the upper right
(northeast) corner along a receiver line. The workstation
XYs are scaled from feet to meters.
SEE ALSO
tim2hed3d
AUTHOR
Paul Gutowski (socon 422) 3146
COPYRIGHT
copyright 2001, Amoco Production Company
All Rights Reserved
an affiliate of BP America Inc.
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