xmplot
Program
ABSTRACT
The X/Motif On-Screen Display program XMPLOT provides a user-friendly method for displaying
seismic data directly on the screen in a format similar to that obtained in hardcopy
displays. Data may be displayed in either color or black and white. Variable scaling
of displays is supported, along with left-to-right or right-to-left orientations.
Multiple data sets may be input and displayed as single displays, overlay displays,
or as "Titan" displays. Selected zoom and variable-timed "movie" displays are also
supported.
Up to 30 data sets may be loaded, plotted, and held in memory for display. A "data
set" consists of any portion of a data file. That is, one "data set" may be the first
record of a data file while the second "data set" is the second record from the same
data file (or even the first record again, displayed with different parameters).
Input
The input to XMPLOT is one or more data files in SIS/USP format. The data may be
of any type that may be displayed in trace format, such as seismic data, velocity
data, or complex attributes.
XMPLOT also reads DISCO format.
Output
On-screen display and CGM's.
PROGRAM DESCRIPTION
Panel Layout
The panel presented by program XMPLOT consists of two separate areas. The first area
is actually made up of three smaller areas: one for the control buttons (the menu
bar) used to control the operations of the program, one for presentation of operational
information (the informational area), and one for presentation of information (record
number, trace number, time, and actual data magnitude of the trace pointed to by the
mouse cursor) about the displayed data (the "odometer").
The second area is the data display area. If the actual display is smaller than this
area, the configuration of the window will not change. However, if the actual display
is larger than this default area, scroll bars, both horizontal and vertical, will
automatically be attached to this area, to accomodate the display. The window itself
may be expanded or reduced in size in the same manner as any other window.
Menu Options
Program operations and display options in program XMPLOT are controlled through popup
or pulldown menus accessed through buttons on the control panel. Descriptions of
the controlling buttons, and of the menus which the buttons invoke, are given below.
FILE button
Use this button to select select data sets to be displayed or to exit from the program.
Data sets may be loaded for individual or for overlay display. To load data for
for individual displays,select the "Load Seismic Data" option. To load data for overlay
display, select the "Load Overlay" option. To load data for Titan display, select
the "Load Titan Data" option. See "File Selection Panels" below for description of
how to select file names.
Load Seismic Data
Use the "Load Seismic Data" option to initiate the "standard" display procedures (displaying
some or all of a data set with any of the display types described below). When this
option is selected, the presents a file selection panel for data set selection, opens
the selected data set, extracts certain header information, and presents the display
parameter panel for parameter completion.
Load Overlay Data
Use the "Load Overlay Data" option to initiate the overlay display procedure. When
this option is selected, the program presents file selection panels for both the backgound
and foreground data sets. When both data sets have been selected, the program opens
the data sets, extracts header information, performs compatibility checks, and presents
the display parameter panel for parameter completion. Display types (see below) are
set to "Wiggle Only" for the foreground data set and to "Sample by Sample Color VD,
no wiggle" for the background data set and the display types on the parameter menu
are made unselectable.
Load Titan Data
Use the "Load Titan Data" option to initiate the Titan display procedure. When this
option is selected, the program presents file selection panels for the wiggle trace,
the red trace, and the blue trace data sets. When all data sets have been selected
(any one data set may be selected two or three times), the program opens the data
sets, extracts header information, performs compatibility checks, and presents the
display parameter panel for parameter completion. Display types (see below) are set
to "Wiggle Only" for the wiggle data set and to "Sample by Sample Color VD, no wiggle"
for the other two data sets and the display types on the parameter menu are made unselectable.
Exit
If the EXIT option is selected, you will be given the chance to
cancel the exit procedures. If "CANCEL" is not selected from the
option box the program is terminated.
DisplayParameters button
Use this button to invoke options to either set or change display parameters or to
change the color scale (invoke the Color Editor). This button may be selected anytime
either of these options is desired. Neither option may, however, be selected until
a data set has been selected. Although the ColorEditor may be selected at any time,
color editting has no effect unless a color display option has been selected (see
Display Types). If the parameter panel is selected when displays have already been
created, the parameters shown and/or modified apply to the current display. Any color
editting, however, changes the color map for ALL color displays.
When the "Display Parameters" option is selected, the display (plotting) parameters
panel is displayed. These display parameters permit flexible design or modification
of the on-screen display configuration. These parameters are described below. The
Color Editor is documented separately and its document is accessed through the "Help"
button on the color editor panel.
Start Record Number
The number of the first record to be displayed. The number of the first record on
the input data set is extracted from the seismic data set when it was selected (see
the description of the File button above) and is entered for this parameter as a default.
End Record Number
The number of the last record to be displayed. The program computes, from line header
parameters, what it thinks is the last record number, assuming sequential record
numbering, and supplies this as a default. It should be corrected as necessary.
Start Time
The time at which the display is to begin. A value of "0" is supplied as default.
End Time
The time at which the display is to end. The program computes the total time
on the trace and supplies this value as default.
Inches per Second (Cm per Second)
Temporal (vertical) display scale. If the Units option (see description below)is
set to English, this scale is in Inches per Second. If the Units option is set to
Metric, this scale is in cm per second. A default value of 2.5 for English units
or 10 for Metric units is supplied.
Traces per Inch (Traces per Cm)
Horizontal display scale. if the Units option (see description below) is set to Englis,
this scale is in traces per inch. If the Units option is set to Metric, this scale
is in traces per cm. A default value of 24 for English units or 10 for Metric units
is supplied.
Maximum Overlap
The maximum deflection of a wiggle trace, measured in traces from the base line for
each trace. Any computed deflection greater than this value is truncated to this
value. A default of "2" is supplied.
Scale Factor
The fraction of the Maximum Overlap which the Reference Amplitude (see below) will
cause. This parameter is used to prevent/cause truncation of the wiggles for amplitudes
greater than the Reference Amplitude. This scaling factor is used for display only
and does not alter the input amplitudes displayed on the odometer.
Reference Amplitude
Select the desired method for establishing the Reference Amplitude for deflection
computation, as described above. If Average Absolute Amplitude is selected, the average
absolute amplitude for each trace is determined and the largest is used. If the Maximum
Absolute Amplitude is selected, the largest sample magnitude is used. If a reference
value is supplied, it is used.
Units
The on-screen display may be scaled either in English (inches per second and traces
per inch) or Metric (cm per second and Traces per cm). Select the units by selecting
the toggle button corresponding to the desired option. The parameter labels and defaults
horizontal and temporal scales will be modified to reflect the choice.
Direction
The on-screen display may be displayed with the first trace either on the left (left-to-right)
or on the right (right-to left). Choose the option desired.
Interpolation
XMPLOT uses interpolation to achieve its variable temporal scale. Three methods of
interpolation are available - quadratic spline (parabolic), cubic spline and no interpolation.
The first two method are both polynomial interpolation procedures, but the parabolic
interpolation is about 1/3 faster than the cubic spline. The "catch" is, however, that the parabolic
interpolation does not display zero-phase characteristics, whereas the cubic spline
does. If your are plotting sparse data (spikes), you'll probably want to choose the
cubic spline for interpolation. Otherwise, you'll probably want to choose the quadratic
interpolation method.
Choose the desired interpolation method by selecting the corresponding toggle button.
Display Type
Several display types are available for displaying the input seismic (trace) data.
To select any of the options, select the toggle button corresponding to the desired
display type. These options are made inaccessible if the current display is overlay.
Select the "OK" button when parameter entry is completed. The data set will be loaded,
plotted and displayed. A slider, showing completion percentage, is displayed while
plotting is in progress.
Odometer Button
Use this button to select the data set for which the amplitudes displayed in the odometer
area apply when using either of the overlay or Titan display options. When this button
is selected, a list of choices (foreground or background for an overlay display, or
wiggle trace, red trace, or blue trace for a Titan display), will appear. Select
the data set desired by selecting the appropriate toggle button on the panel. The
amplitude shown in the odometer area will then be the sample amplitude for that data
set. When neither the overlay option nor the Titan option is being used, no options
are selectable via this button.
Zoom Button
Use this button to initiate or terminate zoom procedures. When this button is selected,
you may elect to "Set Zoom Parameters" or "Dismiss Zoom", as appropriate. These procedures
are described below.
Initiating Zoom
1. Select the "Set Zoom Parameters" option to access the zoom factor parameter panel.
2. Enter the horizontal and vertical zoom factors on the parameter panel.
3. Select the "OK" button to continue or "Cancel" to quit the zoom option.
4. Move the mouse cursor to the area you want to zoom and, press and hold the left
mouse button while dragging the cursor over the area to be zoomed. An expanding box
will follow the cursor to show the area selected.
5. When the desired area has been enclosed in the expanding box, release the mouse
button. After a short delay, a new display area will appear containing the "zoomed"
display. The area selected remains highlighted by the box.
6. Information displayed in the odometer area is derived from the "zoomed" data, with
amplitudes corresponding to the selected dataset.
Clearing the Zoom
1. Select the "Dismiss Zoom" option.
2. The zoom display will disappear and the box on the original display will be
erased
SelectDisplay Button
Use this button to change the display to any of the input data sets, to initiate animation
procedures, or to delete existing displays. These options are described below.
Random selection of data sets
1. Select the "Select display" button to access a list of data sets available.
2. From the list of data sets, select one desired. The on-screen display will change
to show the selected data set. Also, the display parameters panel will be updated
to to reflect the parameters used for this display and, for overlay or Titan plots,
the data set selection will be set to the last selected.
3. Enter this option as often as desired to change the display.
Animation
1. Select the "Animate" button to access a list of data sets available and the animation
timer.
2. The panel containing the list of data sets contains two toggle buttons on the
left side. The left-most of these is used to indicate the current display during
animation and is not selectable. The right-most button is used to select the data
sets to include in the animation. Data sets are selectable/deselectable during animation.
3. Select two or more data sets from the list. The toggle button corresponding to
selections is displayed as depressed and in color (red). A selection is deselected
if selected again.
4. After selecting the desired data sets, use the mouse to select the "Step" button
to step through the selected data displays, or to move the timer slider off zero to
begin timed animation begins. For timed animation, the value shown on the slider is
the delay time, in ms, between frames. It may be adjusted for up to two seconds of
delay. Delay times of less than 100 ms but greater than zero are set, by the program,
to 100 ms to help prevent an overload of the X server. The animation is continuous
while the slider is set to a non-zero setting. The left-most toggles change colors
from the usual background color to red when the corresponding data set is displayed.
5. To terminate timed animation, either move the slider to 0 or select the "Quit"
button. You must use the "Quit" button to dismiss the animation panel and terminate
the anmimation procedure.
Random deletion of displays
1. Select the "delete display" button to access a list of data sets available.
2. From the list of data sets, select the display(s) to be deleted and select the
"Ok" button. The selected display(s) will be removed from memory, making room for
additional displays. If the displays deleted include the current display, the screen
is cleared.
File Selection Panels
Selection of data load options causes one or more file selectiion panels to appear.
This file selection panel is a (scrolled) list of files in the current directory
and of the directories related to the current directory. Select a file by "clicking"
on the file name in the list displayed on the right side of the panel. The directory
may be changed, to see file names by either typing the directory name in the "Filter"
field at the top of the panel or by selecting the appropriate directory from the list of
directories displayed on the left side of the panel (use the ".." entry to back up one level).
Existing files not in the current list may be selected by entering the (fully qualified)
name of the file in the text area at the bottom of the panel.
Select "OK" to load the files (just pressing "Enter" works, too), or "CANCEL" to quit
without taking any action. Use the "Filter" option to change directories to that
entered in the "Filter" text area or to update the list of files in the current directory.
Updating will be necessary when the file you wish to select was created after the
current session of XMPLOT was started. For example, you may want to apply DAVC to a data set
after you get into XMPLOT, so you make sure XMPLOT is a background process, do your thing, and
then select the new data set for display after selecting the "Filter" button on the
File Selection Panel.
Overlay Displays
Overlay displays provide a convenient method of direct visual comparison of two data
sets. In this option, a foreground data set and a background data set are selected.
The foreground data set is displayed as a wiggle trace display, while the background
data set is displayed in sample-by-sample color variable density. No other display
options are available. Note that the foreground and back- ground data set MAY BE
THE SAME, which would be equivalent to displaying the data set with display option
7.
Titan Displays
Titan displays provide a convenient method of direct visual comparison of three data
sets. The data sets are selected as a "wiggle" trace data set, a "red" trace data
set, and a "blue" trace data set. The data sets are displayed with the "red" and
"blue" data sets drawn with positive amplitude VA fill only and the "wiggle" data
set drawn on top. Where the "red" and "blue" data sets are coincident in amplitude,
the VA fill is drawn in green. Selection of the colors used for the VA fills is currently
fixed at red, blue, and green. Use the Reference Amplitude scaling option to ensure
that the displays have appropriate proportional scaling.
Panel Colors and Font
When xmplot begins execution, the color of the panels is set to a default (gray on
green) and the font is set to the default for the window. These characteristics can
be overridden by putting entries into your .Xdefaults file to set them to colors and
fonts of your own choice. For example, the entries would look something like
xmplot30*background: lightblue
xmplot30*fontList: 8x13bold
to set the panel color to light blue and the font to 8x13bold. Note that the program
name (xmplot30 in this case) must agree with the version name of the module being
executed. This name is given in the xmplot panel title. You will have to modify
your .Xdefaults each time the module name changes.
To make the entries apply, enter the command "xrdb -load .Xdefaults" after saving
the modified file.