Occupancy heatmap: from people counts to a floor plan

Spatial Map is a live indoor map that can turn people counts from your sensors into an occupancy heatmap on the building’s own floor plan, one floor at a time. An occupancy heatmap answers “where are people, and how many?” — which rooms, desks, halls or zones are used, when, and how full they get against their capacity.

Three words get mixed up. Occupancy is how many people are in a space at a moment. Utilisation is occupancy over time against capacity — a 12-seat room used by two people all day is busy but under-used. Footfall is how many people pass through. Offices care most about utilisation, venues about peak occupancy, shops about footfall (covered in retail footfall heatmaps).

Most buildings mix two or three: door counters for floors and halls, area or desk sensors where utilisation matters, and Wi-Fi counts as a cheap trend line. More on putting each kind on a plan in IoT sensor floor plan monitoring.

Occupancy data can become personal data quickly — a desk sensor in a single office says when one named person is at work. A few habits keep a project on the right side of colleagues and data protection law:

• Store counts per zone, not identities. Most space questions never need to know who.
• Aggregate small spaces. Report single offices as part of a group, or only above a minimum headcount.
• Process at the edge. Camera and thermal sensors should send numbers, not images.
• Say what you measure. Tell people what is counted, why, and how long it is kept.
• Keep it short. Raw readings for weeks; aggregated trends for longer.
• Ask early. Data protection rules differ by country, and in some countries employee representatives must be consulted before sensors go in.

Sensor placement decides what the heatmap can say. Coverage gaps look exactly like empty space, so plan the layout on the floor plan before you buy:

• Door counters at every entrance to the space you measure. Miss one door and the in-minus-out count never balances.
• Area sensors over the zones that matter, with their footprints drawn on the plan so you can see what each one covers and where they overlap.
• Desk sensors on a representative sample if you cannot cover every desk — one neighbourhood per floor tells you a lot.
• Meeting rooms individually. Rooms are the spaces most often booked and least often used; measure each one.
• Nothing in private spaces. Restrooms, prayer rooms and first-aid rooms stay out of scope.

Put each sensor on the map as a marker at its real position, with its coverage as an area. When a zone looks quiet, you can check in one glance whether it is quiet or simply unmeasured.

A heatmap is drawn from points. Each point adds heat where it sits, scaled by a weight. So the job is to turn sensor output into points with a sensible weight:

1. 1
   One row per sensor or zone

   Give each row a position (longitude and latitude, or the name of the room it measures), a count, a capacity and the time of the reading.

2. 2
   Pick the weight

   The raw count shows where people are. A share of capacity — count divided by seats — shows which spaces are full. Compute it in the source or in a field of the table.

3. 3
   Turn on the heatmap

   In the viewer’s Heatmap control, choose the occupancy layer, weight it by the count or the share field, and pick the floor. “Heatmap and items” keeps sensor markers on top; “Heatmap only” shows just the density.

4. 4
   Or colour the rooms

   For “which meeting rooms are full right now?”, colouring each room by its share of capacity with style rules is clearer than heat. Use both: rooms coloured, heat for the open plan.

Two details make an occupancy heatmap honest on a real floor plan. In Spatial Map, heat stops at walls and closed doors, so a packed room does not spill into the corridor next to it; and the heatmap shows one floor at a time, because stacked floors would blur together. Several layers can share one map, each in its own colour — desks and meeting rooms, for instance — though weighting by a number works with one layer. The indoor heatmap software page covers the control in full.

A convention centre with live occupancy

• Peaks and averages answer different questions. Capacity planning needs the peak; space reduction needs the typical day.
• Look by hour and weekday. Tuesday at 11:00 and Friday at 15:00 are different buildings.
• Reset door counters. In-minus-out drifts; a nightly reset to zero keeps occupancy believable.
• Empty may mean unmeasured. Check sensor coverage before you call a zone unused.
• Alert on what needs action. An in-app alert rule such as “number of people in Hall B above 450” turns a heatmap into something a duty manager acts on.

The Lakeside Convention Center demo has occupancy and environment sensors in its halls, an occupancy log table and a Crowd & Occupancy report; the Harborview office demo adds meeting rooms and space use. Try it on your own plan with a 7-day free trial — Pro is $60 a month for up to four facilities.