================================================================= ========================= PLOTSEGY V2.0 ========================= ================================================================= PLOTSEGY V2.0 Changes to the Program Version 1.0 PLOTSEGY V2.0 incorporates 4 major changes in function: 1) The ability to change the sample rate used or replace it if not found in the SEG-Y binary header. 2) The ability to scale the display of the data as either "trace normalized" or against a "relative amplitude" either calculated or entered by the user. 3) A trace increment parameter. 4) The ability to annotate traces using one of 3 different trace header values. Changes 3 and 4 allow PLOTSEGY to display unstacked SEG-Y data and label it appropriately. Shown in figures 1 - 7 are the user-interface changes seen in PLOTSEGY V2.0. (1) SAMPLE RATE After PLOTSEGY has opened the indicated input file and read the binary trace header information, the sample rate found in the binary header is displayed and the user has an opportunity to change it if desired. The default value found in the binary header is displayed in square brackets (["sample rate", milliseconds]) and may be accepted by pressing . The user may enter a new value at the prompt, or "quit" or "exit". The sample rate accepted will be used in all subsequent calculations. (2A) SCALING - TRACE NORMALIZED Trace Normalized scaling will compute the average non-zero absolute sample value per trace and use that value to represent 1/2 a trace width when plotting that trace's samples. Each sample will be displayed relative to that average value for that trace. (2B) SCALING - RELATIVE AMPLITUDE Relative Amplitude scaling will take either a value entered by the user or a value calculated from a user-defined set of traces from within the input file and use this value to represent 1/2 a trace width when plotting all samples within the data set. (3) TRACE INCREMENT The TRACE INCREMENT parameter allows the user to increment the trace counter through the data. For unstacked data, this allows the user to display individual traces from each ensemble. For example, Baikal line 6 SEG-Y demultiplexed data has ensembles composed of 101 traces: 5 auxiliary channels (traces 1 - 5) and 96 data channels (traces 6 - 101). Ensemble trace 6 is the 1st data trace per ensemble and represents the far data trace. Ensemble trace 101 is the 96th data trace per ensemble and represents the near data trace. PLOTSEGY counts the physical traces in the file, where the first trace in the file is physical trace number 1. PLOTSEGY V2.0 will display ALL traces per ensemble, including the auxiliary traces, so they must be included in calculating a starting trace value. The PLOTSEGY V2.0 parameter 1st_trace_number is the number of the 1st physical trace in the file to display. If the data set is composed of 10 shot ensembles, the near trace for those 10 shots may be displayed by setting the PLOTSEGY V2.0 parameter 1st_trace_number to file trace 101 and the parameter trace_increment to 101. This will produce a display using physical traces 101, 202, 303, 404, 505, 606, 707, 808, 909 and 1010, which represent ensemble trace 101 for shots 1 through 10. A far trace display is possible by setting PLOTSEGY V2.0 parameter 1st_trace_number to physical trace 6 and the parameter trace_increment to 101. This will produce a display using physical traces 6, 107, 208, 309, 410, 511, 612, 713, 814, and 915, which represent ensemble trace 6 for shots 1 through 10. For stacked data, this allows the user to simulate the display more data per screen ("panel") then is physically possible. If the display monitor has VGA resolution, it is capable of displaying 550 traces per panel. If the SEG-Y data being displayed has 1100 traces in the data set, the "entire" line may be displayed by setting the PLOTSEGY V2.0 parameter traces_per_panel to 550 and the PLOTSEGY V2.0 parameter trace_increment to 2. This will decimate the data, displaying every other trace and simulates displaying 1100 traces per panel. *** NOTE *** A negative trace increment value will plot the traces in the reverse order to which they are stored in the file. A trace increment of "-1" and a starting trace number equal to the number of traces in the file will plot the entire data file in reverse order. (4) TRACE HEADER DISPLAYS PLOTSEGY V2.0 annotates traces with the physical trace number within the file, labelled "File Trace", and one of 3 trace header values. The user may select header value CDP, ensemble trace number, or the original field record number (FFID) of that trace. ----------------------------------------------------------------- FIGURES ----------------------------------------------------------------- ---------------------------------------- SEGY INPUT FILE PARAMETERS ---------------------------------------- CURRENT WORKING DIRECTORY: D:\CPGMS\SEGY\P5 CURRENT FILE PATH: D:\CPGMS\SEGY\P5 enter new path, "exit", "-" to use the current working directory or press ENTER to use current file path: ..\DATA CURRENT FILE NAME: enter new name, "exit" or press ENTER to use current: 624-79.SGY 624-79.SGY currently has a sample rate of [ 4.000] msec. Enter a new sample rate if desired. Press to accept current value. sample rate [ 4.000]: ----------------------------------------------------------- FIGURE 1: PLOTSEGY V2.0 SEG-Y Input File Parameters Screen. ----------------------------------------------------------- ----------------------------- DISPLAY TRACE SCALING METHODS ----------------------------- NORMALIZED: PLOTSEGY will average the amplitudes within the current trace being plotted and uses that amplitude to represent 1/2 the trace width for the display of that trace. RELATIVE AMPLITUDE: The user selects a starting trace and the number of traces to use. PLOTSEGY will average the amplitudes found for all samples within that range of traces and uses that amplitude to represent 1/2 a trace width for the display of all traces in the data set. Trace scaling: (1) normalized (2) relative amplitude scaling [1]: 2 ----------------------------------------------- FIGURE 2: PLOTSEGY V2.0 Scaling Methods Screen. ----------------------------------------------- Press any key to accept the current relative amplitude to use for plotting. Enter a new relative amplitude value or press "C" to compute a new one. Current relative amplitude value [ 1.000]: C -------------------------------------------------------------- FIGURE 3: User has selected to scale the data using a relative amplitude to be computed ("C"). -------------------------------------------------------------- Traces in file 624-79.sgy: [493] The relative amplitude is computed by averaging the sample values over a range of traces given by a starting trace number and the number of traces to use. starting trace number: 200 number of traces to use: 10 --------------------------------------------------------------- FIGURE 4: User has requested the relative amplitude be computed from the average of the sample values found in traces 200 - 209. --------------------------------------------------------------- trace [200] average amplitude [134455664.000] trace [201] average amplitude [134324672.000] trace [202] average amplitude [134405600.000] trace [203] average amplitude [133956936.000] trace [204] average amplitude [133936984.000] trace [205] average amplitude [134326336.000] trace [206] average amplitude [134122296.000] trace [207] average amplitude [134137880.000] trace [208] average amplitude [134346800.000] trace [209] average amplitude [134024192.000] ---------------------------------------------------------- FIGURE 5: PLOTSEGY V2.0 display of calculating the average relative amplitude to be used. ---------------------------------------------------------- ---------------------------------------- INPUT FILE CHARACTERISTICS ---------------------------------------- FILE: 624-79.sgy sample rate: 4.000 msec number of samples: 1500 maximum time: 6000 msec bytes per trace: 6240 bytes in file: 3079920 traces in file: 493 scaling: RELATIVE AMPLITUDE scaling factor: 134203736.000 Press any key to continue... --------------------------------------------------------------- FIGURE 6: Input file characteristics displayed by PLOTSEGY V2.0 after computing a new relative amplitude. --------------------------------------------------------------- ---------------------------------------- TRACE PLOTTING TYPES ---------------------------------------- TRACE TYPES: (1) wiggle (2) variable area (3) both trace type [3]: ---------------------------------------- PLOT DISPLAY TIMES ---------------------------------------- minimum time [0]: maximum time [6000]: 1000 timing lines [1000]: 100 ---------------------------------------- TRACE PARAMETERS ---------------------------------------- trace gain [1.000]: 1.5 trace clipping [3]: 1 1st trace number [1]: Maximum horizontal resolution is 550 traces per panel. traces per panel [125]: trace annotation frequency [10]: trace increment [1]: Header value to display: (1) CDP Number (2) Ensemble Trace Number (3) Field File Number header value [1]: ------------------------------------------------------- Figure 7: PLOTSEGY V2.0 Trace Information entry screen. ------------------------------------------------------- ================================================================= ======================== PLOTSEGY V2.1 ========================== ================================================================= PLOTSEGY V2.1 Changes to the Program Version 2.0 (1) PROGRAM STARTUP PLOTSEGY is started at the DOS prompt, and has 3 optional parameters: PLOTSEGY {-p DOS path} {-t DOS file descriptor} {-bw} When started, PLOTSEGY will display a banner page on the user's terminal, which will remain displayed until the user presses any key. Once the user presses any key, PLOTSEGY will display a File Selection Menu (see FILE SELECTION MENU, below). Starting PLOTSEGY with no parameters will display to the user a File Selection Menu displaying all the files in the current directory. Two optional parameters "filter" the files which appear in the File Selection Menu: OPTION DESCRIPTION ----------- ----------------------------------- -p DOS path Allows the user to instruct PLOTSEGY to look in the following directory path for any files. -t file descriptor Allows the user to instruct PLOTSEGY to look for only those files matching the following file descriptor. Starting PLOTSEGY with the "-bw" parameter will display the data in black and white. EXAMPLES: --------- PLOTSEGY This example starts up PLOTSEGY, which will look in the current directory location for files. PLOTSEGY -p c:\project1\segy This example starts up PLOTSEGY, instructing it to use only those files found in the "C:\PROJECT\SEGY" subdirectory. PLOTSEGY -t p*.sgy This example starts up PLOTSEGY, instructing it to use only those files in the current directory location starting with a "P" and having a ".SGY" file extension. PLOTSEGY -t *.sgy -p c:\archive This example starts up PLOTSEGY, instructing it to use all files having a ".SGY" file extension in the "C:\ARCHIVE" directory. (2) FILE SELECTION MENU The File Selection Menu is a list of files available to PLOTSEGY as instructed by the user (see PROGRAM STARTUP, above). The user may navigate through the File Selection Menu as described below: UP ARROW: move up 1 line. DN ARROW: move down 1 line. PAGE UP: move up 1 menu page. PAGE DOWN: move down 1 menu page. HOME: move to 1st menu page. END: move to last menu page. ENTER: select highlighted file. ESC: exit file selection. ================================================================= ========================= PLOTSEGY V2.2 ========================= ================================================================= PLOTSEGY V2.2 Changes to the Program Version 2.1 PLOTSEGY V2.2 will determine which type of SEG-Y data is present using the SEG-Y defined "data sample format code" read from bytes 3225-3226 of the binary coded file header. The SEG-Y defined data sample format codes are shown below: FORMAT CODE DATA SAMPLE FORMAT ----------- --------------------------------- 1 32 bit IBM floating point 2 32 bit fixed point 3 16 bit fixed point 4 16 bit fixed point with gain code ================================================================= ========================= PLOTSEIS V1.0 ========================= ================================================================= PLOTSEIS V1.0 Changes to the PLOTSEGY Version 2.2 Name changed from PLOTSEGY to PLOTSEIS with the additional ability of processing MINI-SOUSIE seismic data files. (1) PLOTSEIS will interpret any file names ending in .MIN as MINI-SOUSIE seismic data files and process them accordingly. (2) PROGRAM STARTUP: new command line argument. PLOTSEIS will display the data with the amplitudes color- coded if started with the command line parameter "-c", as shown below: PLOTSEIS {-p DOS path} {-t DOS file descriptor} {-c} The amplitudes are colored according to the following method: color value = absolute value of the sample amplitude divided by the reference amplitude times 100, i.e., colorValue = abs(sampleAmplitude/referenceAmplitude*100) where the reference amplitude depends on the type of trace scaling specified by the user: TRACE NORMALIZED: the reference amplitude is the average positive sample amplitude found for each individual trace. The colorValue for each sample in an individual trace is determined relative to that value. RELATIVE AMPLITUDE: the reference amplitude is either entered by the user or the average positive sample amplitude found from a user-specified range of traces. The colorValue for each sample in an individual trace is determined relative to that value. Colors are assigned according to the following ranges: colorValue Color 0 - 80 blue 80 -160 light blue 160 - 240 green 240 - 320 light green 320 - 400 red > 400 light red Changing the RELATIVE AMPLITUDE will change how the trace sample amplitudes are colored. Increasing the RELATIVE AMPLITUDE will shift the colorValue to the lower end of the ranges shown above. Decreasing the RELATIVE AMPLITUDE will shift the colorValue to the higher end of the ranges. The TRACE GAIN may be decreased / increased with a corresponding increase / decrease in the RELATIVE AMPLITUDE to maintain the sample horizontal trace excursion.