The pressure atlas

2,433 buildings, two questions each

Every candidate shophouse the screen could find in Bangkok, laid over the Treasury appraisal that decides each one's fate.

Two questions per building: is the ground under it worth more than the median (฿3,568,750), and is the plot shallow enough (under 13.6 m) that a compliant rebuild loses a serious share of its footprint to the setback? The four answers are the four colours — and one of them is the whole essay. This page is the map's own address; every figure on it is computed by the build script, not asserted.

Showing 2,433 of 2,433 candidate footprints. Fill is the Treasury (กรมธนารักษ์) peak appraisal per district; dots are candidate shophouses, coloured by whether the ground under them is worth more than the median (฿3,568,750) and whether the plot is shallower than the median 13.6 m — on a 8 m road, a compliant rebuild steps back 2 m and a shallow plot loses the larger share of it. Morphology is not proof: none of these has been confirmed by survey. Appraised value sits below market, so every figure is a floor.

Worth reconsidering 292 footprints
High land value, shallow plot.
Maximum pressure to demolish — and the plot is shallow enough that a compliant replacement loses a serious share of its footprint to the setback. Demolition here is closest to self-defeating, and it is the owner who is least likely to have been told.
Genuinely exposed 932 footprints
High land value, deeper plot.
The land is worth enough to justify clearing and the plot is deep enough to absorb a setback. On present rules these are the ones that go, and an argument for keeping them has to be made on carbon, tenure or social capital rather than on the code.
Reuse is the easy answer 923 footprints
Lower land value, shallow plot.
Little pressure to clear, and the setback would bite hard if anyone tried. Nothing needs defending here yet — which makes it the cheapest place to test what adaptive reuse actually costs.
Not under pressure 286 footprints
Lower land value, deeper plot.
Neither the market nor the code is currently forcing a decision. Worth surveying precisely because there is time to do it properly.

The districts

The table the essay's embed leaves out. Reconsider is the pink quadrant — high land value on a plot too shallow to rebuild whole; exposed is the ink quadrant — worth clearing and deep enough to survive the setback. Districts are ordered by candidate count.

District	Candidates	Median frontage × depth	Appraisal ฿/m²	Median land under one footprint	Reconsider	Exposed
Phra Nakhonเขตพระนคร	1,281	4.3 × 13.1 m	62,500–250,000	฿3,262,500	144	421
Samphanthawongเขตสัมพันธวงศ์	756	6.0 × 13.7 m	62,500–250,000	฿4,521,875	108	347
Bang Rakเขตบางรัก	153	5.0 × 16.1 m	62,500–250,000	฿4,893,750	15	111
Thon Buriเขตธนบุรี	58	7.1 × 15.2 m	21,250–50,000	฿2,034,688	0	16
Bang Kho Laemเขตบางคอแหลม	56	7.0 × 11.3 m	62,500–250,000	฿4,803,125	25	13
Lat Krabangเขตลาดกระบัง	41	6.9 × 11.3 m	6,250–12,500	฿443,125	0	1
Phasi Charoen	39	8.0 × 13.7 m	8,750–50,000	฿904,750	0	3
Pom Prap Sattru Phaiเขตป้อมปราบศัตรูพ่าย	24	15.2 × 35.5 m	62,500–250,000	฿34,465,625	0	19
Nong Chokเขตหนองจอก	24	11.0 × 21.8 m	3,250–7,500	฿703,300	0	0
Khlong Sanเขตคลองสาน	1	8.0 × 23.2 m	21,250–50,000	฿3,933,375	0	1
All districts	2,433	—	—	—	292	932

Method, in one breath

Candidate footprints screened from Overture/OSM building geometry (frontage and depth are the short and long sides of each footprint's minimum-area bounding rectangle, by rotating calipers), joined point-in-polygon to Treasury Department appraisal bands quoted per square wah and converted at 1 wah² = 4 m². The price axis cuts at the median land value under one footprint, ฿3,568,750; the depth axis cuts at the median plot depth, 13.6 m, where a 2 m setback loss is assumed on an 8 m carriageway. The whole computation is one readable script that runs in under a second with no external calls.

What this is not

Morphology is not proof. A narrow, deep footprint repeating along a street is the shophouse signature, but no field survey has confirmed that any individual building here is one, nor its age, condition or tenure.
Appraised value is the base for transfer tax and sits below market, so every land figure is a floor rather than an estimate.
The setback exposure assumes a road width, because per-plot road widths are not published — the assumption is stated in SPLITS and can be changed.

The data itself

shophouse-pressure.geojson — one point per candidate, quadrant, frontage, depth and land value in the properties · bkk-land-price.geojson — the district appraisal polygons · both regenerated by scripts/build-shophouse-pressure.py and served from this domain, ODbL for the OSM-derived geometry. The full catalogue of every dataset this project serves — sourced, licensed, checksummed — is at /datasets.