Day 15 · Inside out — Health care, from the centre outwards
Walk 1 km at a time out of the old city centre: how density, hospitals and pharmacies change ring by ring — and which thanas pull patients in from their neighbours. Dhaka: 17% of Dhaka people live within 3 km of the centre …. Chattogram: 29% of Chattogram people live within 3 km of the centre ….
Write-up
The question
How do population, hospitals and pharmacies change as you move 1 km at a time from the centre of Dhaka and Chattogram — and which thanas draw patients in from their neighbours?
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
- 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).
- 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.
- 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).
- Centre: Motijheel–Gulistan (90.4125° E, 23.7289° N) for Dhaka, GEC–Kotwali (91.8317° E, 22.3384° N) for Chattogram. Every cell, hospital, clinic and pharmacy is assigned to a 1 km ring by planar distance.
- Ring area = ring disc ∩ city polygon, so cantonment, airport and water do not dilute density; density = people ÷ land area inside the city.
- Per ring: people, area, density, hospitals, clinics, pharmacies, people per hospital, care points per 100,000, pharmacies per 100,000.
- Catchments: each cell is assigned to its nearest hospital; the hospital’s thana gives the flow thana → thana (people-weighted). ‘Served’ = people in the nearest-hospital catchments of the thana; ratio = served ÷ residents.
Findings
Dhaka — Population peaks in ring 2-3 km at 105,822 people per km² — not at the centre itself (ring 0–1 km: 39,533).
Dhaka — The first 3 km hold 17% of residents, 27% of hospitals and 15% of pharmacies: care is more concentrated than people.
Dhaka — Outside 6 km a hospital serves 25,096 people on average, inside it 13,834. The worst single ring is 12-13 km with 87,058 people per hospital.
Dhaka — Care magnets (hospital catchment ÷ residents): Uttara Purba 1.84×, Gendaria 1.73×, Shahbag 1.66×. Senders: Kadamtali (100% of residents are nearer a hospital elsewhere), Hatirjheel (100%), Shah Ali (78%).
Chattogram — Population peaks in ring 2-3 km at 50,328 people per km² — not at the centre itself (ring 0–1 km: 46,276).
Chattogram — The first 3 km hold 29% of residents, 48% of hospitals and 30% of pharmacies: care is more concentrated than people.
Chattogram — Outside 6 km a hospital serves 28,559 people on average, inside it 12,801. The worst single ring is 6-7 km with 106,234 people per hospital.
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