Comparing monitors

The line-up sets every vibration monitor's record of the blast side by side: one lane per monitor, all on the blast's clock, nearest monitor first, with the arrival the plan predicts drawn across them. It is a record section of the blast. It shows at a glance which monitor shook when and how hard, and how sure the platform is of each record's place in time. From it you can pick two or more records and open them in the ViB Analyser together.

The line-up is part of Event Compare, one of your team's beta features. It is by invitation: an owner or admin of your team asks for it under Settings, in Beta features. Until it is on, Compare is not offered.

Open the line-up

• Press Shift+U. With a monitor in focus, that monitor is picked first.
• Select a monitor and choose Compare among its actions, or right-click any monitor and choose Compare. The line-up opens with that monitor picked first.
• Right-click open ground and choose Compare, or find it in the command palette.

Compare is offered only on a blast where at least two monitors have a record the analyser can open: analysed, with its processed data. Each of those monitors gets a lane.

The gather

As the line-up opens, the scene holds still and dims behind it, as it does under the analyser. Each monitor's trace card, the record that stands beside it in the scene, lifts off its unit and flies to its lane, nearest monitor first, and the lane's trace draws out as the card lands. A monitor out of frame has no card standing, so its lane draws out in place.

The line-up's title counts the monitors on the blast's clock. When it closes, the cards fly home to their units, and the scene is yours again. If your computer is set to reduce motion, nothing flies: the line-up opens and closes in one step.

Read a lane

Each lane's header gives:

• the unit's photo and name, and the peak vector sum (PVS) of its record;
• its distance from the blast and its bearing: the direction the ground wave travelled at the monitor, from the blast to the unit, in degrees clockwise from grid north;
• its timing chip: how the record was placed on the blast's clock, and how sure that is (see Timing chips).

Its trace is the record's vector sum, drawn as an envelope: the combined motion of all three axes, which looks the same however the unit was lying.

A lane that has nothing to draw says why: Loading record…, The record could not be loaded, No velocity to draw, or that the recording has a data issue, so nothing is drawn from it.

Order and spacing

Order lanes by sets the order down the page: Distance from the blast (the default), Bearing, Peak (largest first) or Name. A lane with nothing to sort by, such as a monitor with no place on the ground, goes last.

Switch on Space by distance to make the line-up a true record section: each lane's place down the page is proportional to its distance from the blast, so the predicted arrival becomes a straight, slanted line. The lanes then run in distance order whatever the order is set to, traces close together in distance overlap, and lanes with no distance go below the rest.

Time from

Time from sets what t = 0 is, along the ruler at the top:

• Blast clock, the default: true times, in ms from the blast's first planned fire. Ticks along the ruler mark when each hole fired, and each lane sits where its record was placed. A record that could not be placed is hatched and marked Not placed, with no trace.
• First motion: every lane's first motion at 0, to compare the shapes of the arrivals. A record whose first motion could not be found is laid on its trigger and says so: No first motion found: laid on its trigger.
• Peak: every lane's peak at 0.

Under First motion and Peak every record draws, placed or not, because each is lined up by its own shape, not by its time.

The predicted arrival

On the Blast clock, each lane carries a tick where the plan says the first ground wave should reach that monitor: the earliest, over every hole, of its fire time plus its distance to the monitor divided by the wave velocity. With the lanes in distance order, the ticks join into a line across the lanes, with a soft band either side for a wave 25 % faster or slower. Ordered any other way, the ticks stay on their lanes, since a line would zigzag. The arrival needs the monitor placed on the ground and holes with firing times.

A record placed from its first arrival sits on the line by design: that is how it was placed. The line is a check on the others. A GNSS record whose first motion strays well off it points at a monitor in the wrong place on the ground, a plan whose times are not what fired, or a velocity that does not suit the ground.

Timing chips

The chip on each lane says how its record was placed on the blast's clock:

The ± is how sure the placement is, about one standard deviation, against the blast's clock. On the Blast clock it is drawn as a soft band at the record's trigger, so an estimate never passes for a measurement. A placement from the first arrival is typically good to tens of milliseconds, wider the further the monitor stands from the blast. A GNSS lane gives two figures. Between GNSS units is how closely the receivers pin the record to the blast's other GNSS records: about a sample, the figure to compare their arrivals by. To the blast is how well the GNSS records as a group are placed on the blast's clock, which is the wider one; the band on the Blast clock is drawn at that width. The analyser gives the gap between two of them when you analyse them together. How each method works: The blast's clock.

Scale

Scale sets how tall each trace stands:

• Each to its peak, the default: every lane fills its height, to compare the shapes of the records.
• One scale: every lane on one scale in mm/s, printed beside the control as Full scale, to see how the motion dies away with distance.

The plan inset

At the side of the lanes, a small plan, north up, shows the outline of the pattern and a dot for each monitor. Hover a dot to light its lane, or a lane to light its dot, so you keep track of where each record came from while the scene is held.

Scrub

Press and drag across the traces to run one cursor across every lane. Let go on the Blast clock and the scene's playhead moves to that moment, so the replay picks up there when you close the line-up. Changing Time from clears the cursor, since its time means nothing on another axis.

Analyse together

Click a lane's header to pick it, and click it again to let it go. Shift-click picks every lane between the last one you clicked and this one. The first lane you pick is the Primary; click the star on another picked lane to make it the primary instead. The count beside the button says how many lanes are picked.

With two or more picked, Analyse together opens the ViB Analyser over the line-up on the primary's record, with the others laid over it as datasets. Each is placed against the primary by the blast's clock. Under the charts, a chip for each says how the pair was placed and how sure that is, and a row gives the difference in PVS, the two dominant frequencies, and how much later or earlier its ground began to move than the primary's. See Comparing with other monitors for reading them.

In the Visualiser, the compared records are drawn as their vector sums, and their offsets cannot be adjusted. The analyser's previous and next step the primary through the units and keep the same records under comparison: the record you leave joins the compared ones, and the one you step to leaves them.

Close it

Esc steps back one layer at a time:

1. what the analyser holds, such as a focus or a measured span;
2. the analyser's full screen;
3. the analyser, back to the line-up as you left it;
4. the lanes you picked;
5. the line-up itself, back to the scene.

The close button at the top right of the line-up closes it in one step.