OCTAVE HODOPLOT

This program is run in an octave session. Start an octave session and type hodoplot. This program is for the case of two components in the same *.seg file.

 Prompts follow:
1. enter file name.  Example: 1001.seg hardwired as a 6 channel shot record with 3 components
down-hole and 3 components stationary reference phone at the surface.
Down-hole Phone
ch1=Vert
ch2=Radial
ch3=Transverse

Reference Phone
ch4=V
ch5=R
ch6=T

2. GUI, informative.
3. GUI, choose either the down-hole or surface reference phone.
4. GUI, choose component for X-axis, say T
5. GUI, choose component for Y-axis, say R
6. GUI, choose a scale factor, or default
7. GUI, choose a Tmax, say .05 seconds
8. GUI, click continue
9. GUI, choose the next Tmax, say 0.10 seconds 
10. GUI, click continue

KEY POINTS:
* There will always be a sign convention.  Here, on the vertical phone,
upward velocity produces a negative voltage.  Do a tap test for your
equipment.

* The hodoplot.m program is hard wired to relate components to the GUI
choices.  If your phones use different channels for V, R, T, then you may
need to modify the code.  By the way, R and T are just arbitrary labels
considering that down-hole phones will twist there orientation as they
travel up or down the hole.

What you are doing is progressively working down in time, plotting the particle motion. With each step, just change the Tmax value, the Tmin value is automatically adjusted to the last step tmax value. Here the first arrival largest motion is in the direction of the R component. This means that it is mostly aligned with the source blow to the West. The T component is oriented mostly orthogonal to the source.

Figure 9: OCTAVE HODOPLOT: Plotting particle motion on the down-hole horizontal R- and T- components which are channels in the same *.seg file. If components are in different files, use HODO2PLOT program instead (see 6.0.10).