How many people were on the floor.

The count

The interval

What the map rests on

Gaps and privacy

Instrument · people on the floor, minute by minute

Like a thermostat's chart for a house, but for people. Pick a day on the calendar and the chart shows twenty-four hours of the library floor: for every minute the fleet measured, how many people were there, with the range the instrument can honestly give. One paced transmitter, nine receivers, a map calibrated on minutes when the count was known, and a gap wherever nothing was measured. A gap is never a zero.

In plain words Like a thermostat's chart for a house, but for people: a calendar of the days the fleet listened, a twenty-four-hour curve for the day you pick, and a headcount for each minute with the range the instrument can honestly give. A gap in the curve is a gap; nobody fills it with a zero.

The capture format Episodes

2026-08-13. Nothing measured on this day has reached the snapshot.

2026-08-13, hour by hour, library time. "Most people" is the highest estimate inside the hour with its interval. An hour with no measured minute prints a dash, never a zero.
Hour	Measured min	Most people	Min with people
00:00	—	—	—
01:00	—	—	—
02:00	—	—	—
03:00	—	—	—
04:00	—	—	—
05:00	—	—	—
06:00	—	—	—
07:00	—	—	—
08:00	—	—	—
09:00	—	—	—
10:00	—	—	—
11:00	—	—	—
12:00	—	—	—
13:00	—	—	—
14:00	—	—	—
15:00	—	—	—
16:00	—	—	—
17:00	—	—	—
18:00	—	—	—
19:00	—	—	—
20:00	—	—	—
21:00	—	—	—
22:00	—	—	—
23:00	—	—	—

The instrument behind the count · This day as JSON · The calendar as JSON

How to read it

Each receiver divides its two antenna chains frame by frame. The spread of that ratio over a minute is flat when the room is still and wider when something moves; the fleet level is how many times that spread doubled against each receiver's own empty floor, median over receivers. The count is that level read through a map that passes through the labelled states below. Between two labelled states the map interpolates and says so with its interval.

The receivers are resampled and the level recomputed; the band that gives is mapped through the same inverse, then widened to every labelled state whose own spread it touches. Two states that the instrument cannot tell apart share one interval. Above the highest labelled state the top of the interval is open: "3 or more" means the instrument stops counting there.

The anchors. Zero is the certified-empty floor by construction and is never a label.
People	Minutes	Level (oct)	Spread p10 to p90
0	—	0.00	by definition
2	8	0.88	0.50 to 1.18
3	18	0.93	0.48 to 1.21

One integer per minute with an interval, from a piecewise-linear map through the anchors. Zero is the floor by construction. Above the top anchor the upper bound is open.

26
151 min · peak 3

29
122 min · peak 3

31
61 min · peak 3

A minute nobody measured is a gap on the chart and a dash in the table, never a zero. The page publishes a count for a public library floor and the calibration behind it: no position, no device, no address, and the whole page goes dark while a study is running.