Skip to main content

Site plan

An administrator uploads a plan of the site under Site plan and pins the cameras on it. A plan is any image: an aerial photo, a drawing, a floor plan. Once the cameras are on it, three things follow that no camera can do on its own:

  • an action rule can aim a PTZ camera at what another camera saw;
  • a trail on the Investigation page is drawn on the plan, camera by camera, in order;
  • an incident's PDF report carries a page of the plan with the cameras on it.

Nothing about recording or detection depends on the plan. A site without one works as before.

Upload a plan​

Choose a JPEG or PNG of up to 8 MB and 8000 pixels on a side, give it a name, and select Upload a plan. A north-up image makes every heading a compass bearing. The plan is stored in the recorder's database, so a configuration backup carries it.

The Plan section of the side panel shows the plan's name, size, and weight. Rename changes the name. Replace image swaps the picture: every camera's pin is kept, scaled to the new size, but the calibrations on that plan are dropped, since matched points and headings belong to the old picture; the page says so when the size changed. Delete takes every camera off the plan and removes it, after a confirmation.

A site can have more than one plan: Add another plan uploads a second, and a Plan selector appears in the page header to switch between them. A camera is on one plan at a time. Placing a camera that is on another plan drops its calibration there.

Place the cameras​

Drag a camera from the Cameras list onto the plan, or select it and use Place on the plan, then click where it is. Each placed camera shows a pin and a wedge for the direction it faces. PTZ cameras are drawn with a ring around the pin.

  • Heading, degrees (0 up, 90 right) is the direction of the middle of the picture, clockwise from up on the plan, so on a north-up plan it is a compass bearing. Drag the handle at the tip of the wedge, or type it.
  • Field of view, degrees sets the wedge's width. A PTZ camera takes it from its geometry once its heading is measured.
  • Drawn range, plan px is only how far the wedge is drawn.

Save keeps the position. The pin and wedge are a drawing, not a measurement: they say where the camera is and roughly what it covers. The calibrations below are what tie a picture to the plan. Take off the plan removes a camera's pin and, after a confirmation, its calibration with it. Esc backs out of a half-made step. The list beside each camera says whether its picture is matched or its heading measured.

Match a fixed camera's picture to the plan​

Select a placed fixed camera and choose Match the picture (Match points once it has been matched). The camera's current picture and the plan sit side by side. Click a point on the ground in the picture, then the same point on the plan: the base of a gatepost, a drain, the corner of a lawn. Four points are the least that will do; six to eight spread across the picture are better, and they must not lie in a line. Up to 24 are kept. Points on the ground are the whole trick: the recorder treats the site as flat at the camera's scale, so a point on a wall or a roof misplaces everything near it. Undo picture click drops a picture point before its plan point is chosen, and Remove drops a matched pair.

Save points fits the picture to the plan and reports the fit: how far, in plan pixels, it misses the points on average, with each point's own error beside it. A few pixels is a good fit. When the average is over 15 pixels the page calls it a loose fit and names the point furthest off, which was probably clicked on the wrong spot: remove it, click it again, and save. Clear drops the calibration and keeps the pin; Done returns to the plan.

With the fit in place, where a detected object stands, the bottom middle of its box, becomes a point on the plan. That is what a rule aims a PTZ at.

Measure a PTZ camera's heading​

A PTZ camera reports its pan and tilt in its own units, and its geometry (calibrated or trained on Privacy masks) turns those into degrees. What the recorder still needs is which way the camera faces at pan zero, and how high it is. Both are measured by aiming it at known points.

Select a placed PTZ camera and choose Measure the heading (Aim samples once it has been measured). The camera needs a calibrated or trained geometry first; the page says so and links to Privacy masks when it has only the default. Then:

  1. Put a landmark whose place on the plan you know under the crosshair in the live picture: click it in the picture to center on it, or steer with the PTZ panel in the picture's corner. A point on the ground below the horizon is best.
  2. Click that landmark on the plan. The recorder reads the camera's position and keeps the pair as a sample.
  3. Repeat for two or three more points in different directions. Samples at different distances let the tilt say how high the camera is. Up to 24 are kept.

Save samples fits the heading and the height and reports how closely the samples agree, in degrees of pan. Agreement within a degree or two is a good fit; the page warns above five degrees, which usually means a landmark was not centered when it was clicked or the pin is not where the camera really is. It also warns when every sample looked level, so the height is unknown: the camera will still turn toward a plan point but keep whatever tilt it has, so add a sample or two on the ground nearer the camera. Clear forgets the samples and keeps the pin.

The pin's heading follows the fit. Moving the pin afterwards refits the samples to the new position, since each sample is a plan point and a reading.

To check the result, select the camera: while its heading is measured, a marker on the plan shows the point on the ground under the camera's center, and follows the camera as it moves. Switch on Aim here and click the plan: the camera is sent to look at that point through the same path a rule uses, and the page reports the bearing it turned to and how close to the center of the frame the point landed. Aiming is a PTZ operator's action, offered to operators and administrators, and appears on History → Camera changes as PTZ aimed, like any other drive of the camera.

What the plan enables​

  • Aim a camera at the trigger, an action on action rules: when a matched camera detects something, a calibrated PTZ turns to where it stood, with an optional zoom and an optional return to a preset afterwards. See zones and rules. A PTZ with auto tracking on can then follow what it finds there.
  • On the plan, a panel above a trail on the Investigation page, with the trail's sightings numbered at their cameras and a line through them in order. Markers are where the cameras are, not where the subject stood. See events and investigation.
  • A Site plan page in an incident's PDF report, with the cameras on it and the incident's cameras picked out.

Anyone signed in sees the plan and the cameras they may see on it. Placing and calibrating are administrator's actions. The plan and placements are also available to integrations; see the API reference.