Color Plotting83 Unisec User Guide

Color Plotting

Color display modes

There are two color display modes for seismic traces: • Color Background: a color trace is displayed behind the wiggle trace. The color trace data is either derived from the same trace data used to draw the wiggle or a second source. Each sample is colored with a rectangle equal to one trace in width and one sample in height. This mode is sometimes referred to as Variable Density color. • Color VA fill: the wiggle trace is color VA filled in either/ or peaks and troughs. Like background color fill, the color trace data is either derived from the same trace data used to draw the wiggle or a second source. In both modes the wiggle is displayed in black as a conventional wiggle trace. The color display modes are controlled by the DISP keyword on the PARMS statement: Examples

PARMS, DISP=WCB produces a black wiggle with color background. PARMS, DISP=WCPT produces a black wiggle with color VA ﬁll of the peaks and troughs. PARMS, DISP=CB produces a color background only, no wiggles.

Color Trace Data Scaling (CCLASS)

The CCLASS allows you to specify a relationship between ranges of trace data values and colors plotted. The class intervals are automatically annotated on the color scale. CCLASS is optional when the auto scaling (AUTOSC) function is used. In this case, if the CCLASS is omitted, the minimum and maximum is automatically derived from the trace data. Format

CCLASS, title = (min TO max [BY interval]) Where: title = color scale title (maximum 40 characters). min = minimum data value.

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max = maximum data value. interval = optional increment for interval data values from min to max, if increment is not speciﬁed then range of values is evenly distributed over the number of colors available in the selected color table. Example

CCLASS, COLOR AMPLITUDE = (500 TO 3500) causes the following colors to be assigned to trace data values: Color Number Range 1 < 500 2 500 - 1000 3 1000 - 1500 4 1500 - 2000 5 2000 - 2500 6 2500 - 3000 7 3000 - 3500 8 > 3500 This example assumes that the number of colors in the selected color table is 8.

Color Scale

On both sides of the seismic display a color scale (legend) is displayed showing the color table selected. The scale begins at the top with color number 1 and continues downward until all the colors (up to 64) have been displayed.

Color Scale Annotation

If the CCLASS is used, the COLOR SCALE is automatically annotated using the title and list values from the CCLASS statement. Otherwise, the title and values will be accessed via the entity name CSCLT (title) and CSCLA (values). In this way, they may be extracted from tape or manually entered as follows: Format

EVALS, CSCLT = title, CSCLA

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CSCLA DATA text 1, text 2, ...... text n Where: title = title string (maximum 40 characters), plotted vertical alongside the color scale. text = text (maximum 40 characters) to be placed by each color square. Example

EVALS, CSCLT = COLOR AMPLITUDE, CSCLA 1000, 2000, 3000, 4000, 5000, 7500, 9000, 10500, 14000

Color Tables

Deﬁning Colors (DEFINE, COLORS)

UNISEC requires a color table to translate color numbers to combinations of the primary colors. In this table, each color is deﬁned in terms of the mix of primary colors used to create each color. Format

DEFINE, COLORS[, COLSYS=CMY] c1,m1,y1, c2,m2,y2 ...... cn,mn,yn Where: cn = shade of cyan to be used to create color n. mn = shade of magenta to be used to create color n. yn = shade of yellow to be used to create color n. Shades range from 0 to 16 with 0 normally being the lightest and 16 the darkest. OR DEFINE, COLORS, COLSYS=B b1,b2, ...... bn Where: bn = shade of black, from 0 to 16.

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DEFINE, COLORS, COLSYS=BCMY bl,cl,ml,yl, bl,c2,m2,y2...... bn,cn,mn,yn Where: bn = shade of black to be used to create color n. cn = shade of cyan to be used to create color n. mn = shade of magenta to be used to create color n. yn = shade of yellow to be used to create color n. or

DEFINE, COLORS, COLSYS=RGB r1,g1,b1, r2,g2,b2 ...... rn,gn,bn Where: rn = intensity of red be used to create color n. gn = intensity of green to be used to create color n. bn = intensity of blue to be used to create color n. Intensities of RGB range from 0 to 100 with 0 normally being the lightest and 100 the darkest. There may be up to 64 colors in each color table. If one line ﬁlls up, the numbers may spill over into the next line until all the colors are deﬁned. Example

DEFINE, COLORS, COLSYS=B 1, 5, 9, 13 defines a color table of 4 colors. Note that each color is comprised of a black component only. This type of color table is useful for monochrome plotting and using gray scale VA fill. DEFINE, COLORS, COLSYS=CMY 0,0,0, 0,16,0, 0,15,0, 0,13,0, 0,11,0, 0,9,0, 0,7,1, 0,16,16, 0,12,15, 0,9,14, 0,7,12, 0,5,10, 0,3,10, 0,2,10, 0,1,10, 0,0,11, 1,0,11, 2,0,10, 4,0,10, 6,0,9, 8,0,10, 10,0,11, 12,0,11, 14,0,11, 13,0,6, 11,0,4, 9,0,1, 7,0,0, 5,0,0, 3,0,0, 1,0,0 defines a color table of 31 colors. Color number 1 is comprised of shade values of 0 for cyan, magenta and yellow, color number 2 is comprised of shade values of 0, 16 and 0 for cyan, magenta and yellow, color number 3 is comprised of shade values of 0, 15 and 0 for cyan, magenta and yellow and so on.

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Color Table File

This file which is normally named COLTAB.TXT is comprised of 80 character lines, which may be created and edited by the text editor. The file can contain several color tables, one for each scheme to be used. For instance one scheme may be used for colored frequency displays while another may be for colored amplitude displays; however, only one table may be specified per display job. Each record (line) is 80 columns and begins in column one and may extend to column 80. Format

***color definition name 1 DEFINE, COLORS . . (color table 1) . . ***color definition name 2 . . (color table 2) . . ***color definition name m . . (color table m) . . Example

***AMP DEFINE, COLORS= 0,0,0, 0,16,0, 0,15,0, 0,13,0, 0,11,0, 0,9,0, 0,7,1, 0,16,16, 0,12,15, 0,9,14, 0,7,12, 0,5,10, 0,3,10, 0,2,10, 0,1,10, 0,0,11, 1,0,11, 2,0,10, 4,0,10, 6,0,9, 8,0,10, 10,0,11, 12,0,11, 14,0,11, 13,0,6, 11,0,4, 9,0,1, 7,0,0, 5,0,0, 3,0,0, 1,0,0 ***POLAR DEFINE, COLORS= 0,0,0, 0,13,0, 0,9,0, 0,6,0, 0,3,0, 0,1,0, 0,0,0, 1,0,0, 3,0,0, 6,0,0, 9,0,0, 13,0,0 ***GREY DEFINE, COLORS, COLSYS=B 1, 5, 9, 13 END deﬁnes two color tables, the ﬁrst named AMP is comprised of 31 colors and the last named POLAR of 12.

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Trace Data Color Input

Color Input Modes

UNISEC allows color trace data to be specified in one of three modes. They are single trace, dual trace, or dual file mode, where: T = dual trace color input mode F = dual file color input mode blank = single trace color input mode (default) Example

TAPE, STYPE=R, BPS=4, CINPMODE=F indicates the seismic color input is in the dual ﬁle mode i.e., 1 ﬁle for seismic amplitude and 1 for color, and that the samples are in real*4 format.

Single Trace Mode

In this mode the amplitude and color information are contained in a single trace. STYPE may be either C (multiplexed samples) or I or R in which case conversion of amplitude to color indices is controlled by the CCLASS statement.

Dual Trace Mode

In this mode the amplitude is contained in one trace followed by a second trace representing color. The conversion of sample to colors of the second trace is controlled by the CCLASS statement.

Dual File Mode

UNISEC allows a second file to be specified as the source of the color trace data to be used for background and VA color fill. The first or primary input file represents amplitude which can be plotted as wiggle and/or VA and the second file which is read concurrently to the first is plotted in color. Conversion of the samples to color indices is controlled by the CCLASS statement. The second input file must be formatted as follows: • The file and record structure of the secondary input file must be the same as the primary seismic input file.

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• The reel and trace headers must be of the same length and content. In other words, the values in the second must be identical to the values in the ﬁrst. • Sample formats must be the same in both ﬁles, such as 16 integer, 32 IBM real.

Trace Color Data Format

The format, length and content of the Reel and Trace headers for color plotting is determined by the DEF.TXT ﬁle just as it is for black and white plotting. The format of the samples is speciﬁed by the STYPE keyword on the TAPE statement. For color plotting, STYPE may be one of the following: • I: integer (BPS = 1 or BPS = 2) • R: real (BPS = 4) • C: color (BPS = 2 or 4) Example

TAPE,...... STYPE = I, BPS = 2 speciﬁes the sample format to be 16 bit integer.

Single Trace Data Color Format (STYPE=C)

This trace data format, which can only be used in the single trace input mode, allows for color trace data to be input where the amplitude and color data samples are multiplexed. The number of bytes per sample can be either 2 or 4. The 2 byte data format is as follows: bytes 1 - m = trace header data, where m is the trace header length bytes m + 1 = amplitude of sample 1 bytes m + 2 = color of sample 1 bytes m + 3 = amplitude of sample 2 bytes m + 4 = color of sample 2 . . . bytes m + 2n-1 = amplitude of sample n bytes m + 2n = color of sample n The amplitudes are signed 8 bit integers in the range of plus or minus 256 and the colors are integers in the range of 1 to 64. These amplitudes will be plotted as a conventional black wiggle trace with color superimposed on the wiggle trace

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either as a background fill or VA fill as specified by the display mode (DISP) parameter.