Example bplt

There is a wide range of amplitude variation in most data. Program bplt plots the numbers as given. Here is an example using the “postscript” choice of “idev”. Figure 1 shows the plot produced.


bplt twav.seg 1 1 2 1 78 0 .2 1 400 200 5 2


Figure 1: Example use of bplt to generate Post Script plot of down-hole data. Traces are plotted by geophone elevation. Data from a Boise River gravel borehole, B5.
\includegraphics[scale=1]{FigureA}

We can zoom in, and plot a single trace. Doing so illustrates how much the data have been plotter clipped. For example, Figure 2 a single trace, number 41 (geophone at about 840 m elevation).


bplt twav.seg 1 1 0 41 41 0 .20 1 1500 300 5 2


Figure 2: Example use of bplt to focus in on a single signal, trace 41.
\includegraphics[scale=1]{FigureB}

Several arguments on the command line have changed. The first and last trace change from 1-78 to 41-41. The “amp” option changed from 400 to 1500. The larger the number, the smaller the deflection produced on the plot. Before, a value of 400 would plot at 1 trace spacing, now a larger sample value (1500) plots one trace deflection. But, there is a limitation on this, the plotter clip. The “percnt” option sets a limit the clips the plot of a sample value in terms of trace spacings. For example, in Figure 1, this was set to 200%, or 2 trace spacings. This is done to prevent traces plotting over each other. When we plot a single trace, as in Figure 2, we use two arguments to bring the entire amplitude range for that trace into view. We expand the permitted deflection to 300%, and set the plot deflection for a single trace spacing to require a larger amplitude (1500)