Install guide

Creating ‘Live Trace’ Outlines
The Default ‘Live Trace’ Algorithm
The default algorithm is designed to display the actual extent of 2D or 3D seismic traces,
rather than the navigation extents. In the 2D case, the output shows exactly which lines or
parts thereof have the specified processed level.
In the 3D case, the output attempts to show the exact shape or outline where traces exist
within the rectangular project limits. The 3D algorithm operates by walking clockwise
around the outside of the survey, until it returns to the starting point. The algorithm does
not read every trace, which makes it considerably faster, but it consequently cannot
handle the following scenarios:
• Surveys where e.g. every 2nd line or trace is loaded
• Internal holes within the survey
• Non-contiguous pieces of seismic data
• Zero-valued traces, i.e. real traces with zeros, as distinct from absent or null traces
The default algorithm therefore produces reasonable outlines in the majority of 3D cases,
but will not always succeed. An alternative algorithm is provided to address this and is
described further overleaf.
Using the Default Algorithm in Batch
WOW aims to dynamically create Web pages or images on the fly, i.e. without resorting to
static, pre-created files. Seismic trace outlines present a real challenge in this regard. 3D
volumes containing many millions or traces may not complete within the patience
threshold of a typical user.
A batch mechanism is therefore provided to auto-generate the live trace outlines as png
images, or if 3D, as shapefiles, ASCII coordinate files or ZGF pictures.
Options are provided to generate outlines in these formats for a single volume, all volumes
within a project or for all projects.
To generate a single outline for 2D or 3D, use utility seisLTO, with usage:
seisLTO owproj survey gtype seismic ?stride? ?delta?
?lineinc? ?traceinc? ?xsize? ?padding?
?outfile? ?zgfout? ?picout? ?shapetype?
<owproj> OpenWorks project name
<survey> SeisWorks survey name
<gtype> 2D/3D
<seismic> seismic file name or proclev, e.g. mig0801.3dv or mig080001
<stride> look-ahead factor (default 25 traces – 3D only)
<delta> thinning distance (default 10 traces – 3D only)
<lineinc> line increment for symbol posting (default 100 – 3D only)
WOW 5000.0.1.11 Release Notes Page 57 of 104 March 2014