How to explain a population map to a board in five minutes

Lead with the decision, not the map. Say in one sentence what the map is for ("we have two districts to choose between"), give the one number that matters for each, then show the map as the evidence. Tell the board what one coloured cell is, what the darkest colour means in residents, and what a blank area means. If you do those four things before anyone asks, the map does its job: it shows where people live, and the discussion moves on to whether to act.

This is for the analyst, strategy lead or founder who has to present a heat map of residents to directors, investors or a council committee. Directors are quick readers and short of time. They will form a view from the colours in the first ten seconds, so the slide has to be built so that the first impression is the right one.

What a board is actually looking at

A population map from xMap Flows is built from small hexagons of about 0.1 km² each, roughly the size of one or two city blocks. Each hexagon holds an estimate of the people who live in it, with men, women and nine age groups. Coloured by residents, the map shows where homes are dense and where they thin out.

Three things are not on it, and a board will assume they are unless told:

• Not daytime crowds. It counts where people live. An office district can be nearly blank at the same time as it is packed at lunch. If the decision depends on who passes by, footfall is a separate measure.
• Not spending power. The grid gives numbers of people and their ages, not incomes.
• Not every country. Population figures exist in some countries only, among them France, Canada, India, Thailand, Egypt and Australia, and not in the United Kingdom or the United States. A blank country is missing data, not an empty country.

Building the slide

1. Title as a sentence. "The east district has about twice the residents of the west, in the same area" beats "Population heat map". The title is what gets remembered.
2. One number per option, large. Residents in each candidate area, from the same-size areas. If age matters, add one share, such as children under 20 or over-60s, not all nine groups.
3. The map, with your areas drawn on it. Outline the options. Keep street names faint and add two or three landmarks people know, such as the station or the river.
4. A legend in residents per hexagon, with three or four steps at most, and one line under it: "Each cell is about 0.1 km². Blank means nobody lives there or there is no data."
5. The source and month in small type, and the words "modelled estimates". Directors respect a stated limit more than a hidden one.

A worked example in Lyon

This example is made up. A regional bakery group is choosing between two districts of Lyon for its next shop: one on the hill north of the centre, one in the newer quarter to the south. The strategy lead draws both on the map as shapes of the same size, about 2 km² each, and runs Demographics on them.

Invented figures, for illustration only.

The slide title says: "The north district has nearly twice the residents; the south quarter is younger." The map below shows the north as a solid block of colour and the south as a darker core around a new housing area with lighter edges near the rail yards. The lead says out loud that the rail yards are blank because nobody lives there, before anyone asks.

The board's discussion then turns, as it should, to what the bakery sells and who buys it, not to what the colours mean.

The four questions a board will ask

"How accurate is this?"

Say it is a modelled estimate at a fine scale, reliable for comparing areas and less so for a single block. Then point out that the decision rests on totals over many cells, where small errors tend to even out.

"Why is the centre so pale?"

Because the centre is offices, shops and stations, where few people live. Have a sentence ready on footfall if the business depends on passers-by.

"Is this up to date?"

Give the month the figures were read. Mention any large new housing you know of that the estimate may not yet show.

"What about the competition?"

Have a second slide that puts the count of competitors next to the residents of each area. Residents alone say how big the pool is, not how many others are fishing in it.

Mistakes that confuse a board

• A colour scale stretched by one cell. One very dense tower block can push every other cell into the palest colour. Cap the top step, or use steps you choose rather than automatic ones.
• Comparing areas of different sizes. A larger shape always has more people. Draw options the same size, or show people per km² next to the total.
• Red for "many people". Boards read red as danger. A single colour that darkens with more residents reads as "more" without alarm.
• Too many layers. Residents, competitors, roads and sales on one map is four slides squeezed into one.

Getting the map and the numbers from an AI employee

An AI employee can prepare the material for the slide and refresh it before each meeting.

1. Schedule, once, or each quarter before the board meets.
2. Area of interest with the candidate areas drawn as shapes of the same size.
3. Demographics set to Totals for each area, which gives residents, people per km² and the age groups for each shape.
4. A second Demographics block on the same area, set to Every hexagon, feeding Show on a map with the heat view weighted by population.
5. xMap LLM working on the whole list, told to write three plain sentences comparing the areas, using only the figures given.
6. Make a report as slides, which carries the summary, the figures and the map with your logo.

What lands in your inbox is a short PDF deck with the totals per option, the written comparison and the saved map, which you can open and zoom before deciding which view to put on your own slide.