Commands
Data Selection
Output
Range axis
Time axis
Traces
Labeling/Annotation
Travel Time curves
Multiple Plots
Muting
Interactive Picking
Name
Pltsegy - plot SEG-Y format seismic data.
Synopsis
pltsegy command_file
Description
Pltsegy is a flexible program to produce variable area plots (i.e. fill in the wiggles), straight wiggle plots, or pixilation of seismic data stored in SEG-Y format on disc. Pltsegy allows multiple record sections to be plotted to the screen or to a PostScript file. It allows the addition of travel time curves and labels to the basic plot. Pltsegy supports all plotting devices that are defined in plotlib but is best suited to raster devices such as the screen and laser printer plots.

Pltsegy works on the principle of sensible defaults so that most commands do not need to be specified unless a certain effect is required.

pltsegy is a short shell script in your path, e.g. ~/bin, that is a wrapper for two programs that actually do the record section plotting. The first program parses the user understandable input file and converts it to an intermediate ascii file that is read by the plotting program. The shell script has been created (see below) the user need only be concerned with creating the input command file.

Commands
A synopsis of commands is given below, grouped according to function. All commands for a single plot must appear between a plot-end$ pair in the input file (see EXAMPLES below). The commands for a single plot will be referred to as a plot-end$ list. As many plots as the user requires may be specified in the input file each given by its own plot-end$ list.

Most commands follow a simple name = value; syntax (N. B. both the "=" and ";" are required although spaces are optional). The values are of 4 basic types - string (s), integer (i), real (r), and logical or boolean (b). The type expected by a given command appears in parentheses after the command name. In general, a string value may optionally be delimited by single quotes, "'", as for fortran strings. Cases where single quotes are required for strings are noted with the relevant command synopsis. A boolean value may be given as f, false, t, or true. In general all commands and values are case insensitive. One exception is file names since UNIX is case sensitive.

Certain commands, such as label, are defined as structures and require multiple input values. The arguments expected for structures are given in the definition of the command. The individual elements of a structure may be separated by spaces or commas.

General
Whether a new plot is output with its own plot frame depends on the setting of the advance plot command, advplt. If advplt is true then a new frame is produced and almost all input parameters are reset to their defaults. If advplt is false then plotting continues within the current plot frame using the current time and range scaling. This option allows the user, for example, to overlay multiple travel time curves on the same set of data.

The only command list other than plot-end$ list that is recognized by pltsegy is a hole-end$ list which introduces commands specifying regions of the data to be muted during plotting. A hole-end$ list is required following the current plot-end$ list if filtering/muting is specified using ifilc (see below).

An input file may include comments by using an left brace, "{". Anything between a left brace and the end of a line is treated as a comment and ignored.