Open Lab›#30DayMapChallenge 2026›Day 10 · Prompting only — One sentence, one health map
Web map & dashboard Day 10 · Prompting only © CC BY 4.0 10 November 2026

Day 10 · Prompting only — One sentence, one health map

A single plain-English prompt, a full analysis: how far people in Dhaka and Chattogram live from a hospital, clinic and pharmacy. Dhaka: 77.9% of 10.3 million people live within 800 m (10 min walk) of a hospital. Chattogram: 60.7% of 3.3 million people live within 800 m (10 min walk) of a hospital.

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Write-up

The question

How far do the people of Dhaka and Chattogram live from a hospital, a clinic and a pharmacy — and which thanas have the longest walk?

Data

BD Hospital Dataset (hospitals, clinics, pharmacies), fire stations, garment factories, economic zones and major roads from the GIS Data folder; BBS Population and Housing Census 2022 thana populations; city-corporation boundaries. The registry is incomplete and urban-biased; population per 250 m cell is a dasymetric model; distances are straight lines in UTM 46N.

Methods

  1. Study areas: the two Dhaka city corporations (DNCC + DSCC, 53 thana polygons, 10,250,630 people) and Chattogram City Corporation (15 thanas, 3,273,329 people), BBS Population and Housing Census 2022. White gaps on the maps are outside the corporations (cantonment, airport, water).
  2. Health facilities: the BD Hospital Dataset in the GIS Data folder, split into hospitals, clinics and pharmacies from the type and name keywords; pharmacies within 25 m of each other merged; an ‘emergency / 24 h’ flag from the name and type. Dhaka: 475 hospitals, 507 clinics, 2,049 pharmacies, 44 fire stations. Chattogram: 160, 51, 405 and 24.
  3. Where people live: the census gives thana totals only, so each thana total is spread over a 250 m grid in proportion to a Gaussian kernel (σ = 400 m) of settlement proxies — mobile-phone towers, mosques, schools, health points, pharmacies, hospitals — plus a small floor. Cell sums equal the census total exactly (checked).
  4. The prompt: written first and kept verbatim (shown on the map). It names the data (BD hospital dataset, census), the unit (250 m cell), the measure (distance to nearest hospital, clinic, pharmacy), a threshold (10 minutes) and the outputs. Every vague word in a first draft (‘health’, ‘access’) was replaced by a number or a layer.
  5. Coverage curves: people-weighted share within 100–3,000 m for hospital, any care, pharmacy and emergency care; thana tables with median distance, % within 500/800/1,000/2,000 m, people per hospital, care points per 100,000.

Findings

Dhaka — 60.2% of Dhaka residents are within 500 m of a hospital, 77.9% within 800 m (10 minutes on foot) and 93.1% within 2 km. The median resident is 395 m from the nearest hospital; the 90th percentile is 1.6 km.
Dhaka — Adding clinics lifts 800 m cover to 81.7%; pharmacies reach 78.8% of people within 800 m — pharmacies are the first door.
Dhaka — Farthest thanas (median resident): Uttarkhan 2.4 km, Demra 2.2 km, Turag 1.6 km, Khilkhet 1.6 km. Only 4.9% of Uttarkhan residents are within 800 m.
Dhaka — Most people per hospital: Turag (259,110 people for 1 hospital), Hazaribag (200,482), Shah Ali (151,279). The simple city average hides this: crowding is a thana story.
Chattogram — 41.4% of Chattogram residents are within 500 m of a hospital, 60.7% within 800 m (10 minutes on foot) and 93.0% within 2 km. The median resident is 612 m from the nearest hospital; the 90th percentile is 1.8 km.
Chattogram — Adding clinics lifts 800 m cover to 70.1%; pharmacies reach 73.8% of people within 800 m — pharmacies are the first door.
Chattogram — Farthest thanas (median resident): Pahartali 1.6 km, Bayejid Bostami 1.2 km, Chattogram Port 1.2 km, Halishahar 1.2 km. Only 21.1% of Pahartali residents are within 800 m.

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