The five plates, read on their own

A specimen, not client work.

These are the five plates of the descent through Soho and the West End, drawn without the 3D model. Each says how its layers are known, what it cannot say and where its files are.

Plate I · Measure
Plate II · Locate
Plate III · Compare
Plate IV · Measure
Plate V · Compare

How sure is each answer?

observedSolid lineMeasured directly: a sensor, a survey or a walk.
sourcedSolid line with a source tickTaken from a named, dated dataset someone else maintains.
derivedLong dashCalculated from observed or sourced layers by a stated rule.
modelledShort dashPredicted by a model, with its validation scheme and limits stated.
inferredDotted lineAssumed from context, with the assumption written down.
illustrativeHatch or halftoneDrawn to explain, not to measure.
not knownFog stippleLeft as fog, never given a value.

Every plate and stage layer carries one of these marks. A limit is part of the answer.

Plate I · Measure

Plate I · Measurederivedsourced

One overpass: a 250 m sample in Soho reads 6.6 °C above a 250 m sample in Regent’s Park.

Landsat 9 · 10 Jul 2025, 10:52 UTC · about 33 m display cells, nearest-resampled from 100 m thermal pixels · two 250 m-radius local samples, not whole-park, whole-Soho or land-cover statistics

250 m-radius local sample

Median, quartiles and median per-cell provider uncertainty (a retrieval value per cell, not a confidence interval for the median or the difference)

Regent’s Park: 36.7 °C · 35.8 to 37.5 °C · 2.4 K
Soho: 43.3 °C · 42.8 to 43.7 °C · 3.3 K

One native Landsat thermal pixel, 100 m across, at the same scale. Each value mixes several roofs, streets and trees.

Land-surface temperature, display palette 32 to 46 °C, ticked at the two medians; the values shown lie between 29.5 and 44.7 °C. Values below 32 °C take the first colour.

The quartile ranges do not overlap. One overpass: a descriptive contrast, not a significance test or a cooling effect.

Cannot say: air temperature, which building is hot, or that the park cools Soho.How each layer is known: derived (surface temperature display cells and the two local samples); sourced (building outlines).What I still need to know. An independent field reference: the thermal walks and radiometry my research proposal sets out, proposed and not deployed.Landsat Collection 2 Level-2 image courtesy of the U.S. Geological Survey, public domain. Sample centres and building outlines © OpenStreetMap contributors, ODbL 1.0.Inspect: london-surface-temperature-samples.json, london-climate-manifest.json, soho-twin.json.Surface heat, 10 Jul 2025, 100 m (Public domain); 250 m local samples (Public domain; ODbL 1.0); Buildings, streets, water (ODbL 1.0), retrieved 7 October 2026.A specimen, not client work. Related service: Applied environmental research.

Plate II · Locate

Plate II · Locatemodelledsourcednot known

Tidal flood zones line both banks of the Thames; within the Soho frame they touch only its south-east corner. Surface water, the question these streets still raise, is not loaded.

Environment Agency Flood Map for Planning · Flood Zones 2 and 3 from the sea (tidal Thames) · ignoring defences · retrieved 12 Oct 2026

Zone 3: 0.5% or more a year from the sea, ignoring defences
Zone 2: 0.1% to 0.5% a year from the sea, ignoring defences
Thames, mapped water
Surface-water flooding: not loaded. Fog means not known, not safe.

Cannot say: depth, a flood event, the effect of defences, or surface-water risk.How each layer is known: modelled (flood zones); sourced (buildings, bridges and the Thames); not known (surface water).© Environment Agency copyright and/or database right 2025. All rights reserved. OGL v3.0, retrieved 12 Oct 2026. Buildings, streets and the Thames © OpenStreetMap contributors, ODbL 1.0.Inspect: westminster-pilot-manifest.json, soho-flood.json.Tidal flood zones 3 and 2 to the Thames: likelihood, not an event (OGL v3.0); River Thames, mapped water (ODbL 1.0), retrieved 12 October 2026; Westminster mapped features (ODbL 1.0), retrieved 9 October 2026.

Plate III · Compare

Plate III · Comparesourcedinferred

Around Piccadilly Circus, 286 of 507 buildings have no mapped height; the model gives each two storeys.

OpenStreetMap buildings, 7 Oct 2026 · levels mapped (solid outline) or assumed at two storeys (dotted outline, flat tint) · counted by footprint centre (mean of the ring's vertices) inside this plan

Levels mapped
Levels assumed: two storeys

Across the whole Soho frame, 1,496 of 3,854 buildings have assumed heights. The London Pavilion, chapter 04, has four mapped levels.Cannot say: what any building is made of, its age, or its real height where levels are assumed.How each layer is known: sourced (footprints and mapped levels); inferred (assumed levels, dotted outline).What I still need to know. Mapped levels for the 1,496 buildings whose height is assumed.© OpenStreetMap contributors, ODbL 1.0, retrieved 7 Oct 2026.Inspect: soho-twin.json, piccadilly-landmarks.json.Buildings, streets, water (ODbL 1.0), retrieved 7 October 2026.A specimen, not client work. Related service: Applied environmental research.

Plate IV · Measure

Plate IV · Measuresourcedinferredmodelled

With its mapped form and an assumed fabric, example insulation and glazing cut calculated heat flow by about three-quarters.

OpenStreetMap footprint, 7 Oct 2026 · declared example fabric · steady transmission, Q = U × A × ΔT at 15 K

Example fabric	U, W/m²K	kW at ΔT 15 K
Walls 1,335 m² opaque
Before: 0.215 m masonry	2.134	42.7
After: + 0.12 m insulation	0.257	5.1
Roof 955 m²
Before: deck + 0.03 m insulation	1.022	14.6
After: + 0.12 m insulation	0.227	3.3
Glazing 445 m², 25% of walls
Before	2.8	18.7
After	1.4	9.3
Total transmission		76.1 kW to 17.7 kW

U in W/m²K to three decimals; kW computed from unrounded U-values and areas.

Mapped footprint
Before: example fabric
After: added insulation and glazing

Plan: roof 955 m², perimeter 139 m; four mapped levels at an assumed 3.2 m, 12.8 m.

Cannot say: what the Pavilion is really built from, its energy use, ventilation, solar gains or an EPC rating.How each layer is known: sourced (footprint, levels); inferred (storey height); modelled (assemblies and heat flow, not calibrated).What I still need to know. A survey of what the Pavilion’s walls and roof are made of.Footprint © OpenStreetMap contributors, ODbL 1.0. Assemblies and U-values are declared examples on this site.Inspect: piccadilly-landmarks.json, soho-twin.json.Buildings, streets, water (ODbL 1.0); Envelope transmission (Computed on ODbL 1.0 geometry), retrieved 7 October 2026.

Plate V · Compare

Plate V · Comparederivednot known

A circle puts the school inside five minutes; along mapped streets it is 5.8 minutes.

OpenStreetMap walking network, 7 Oct 2026 · declared 1.3 m/s · one band, 5 minutes · clipped at the frame edge

Streets within 5 minutes
390 m circle, the same 5 minutes in a straight line
Beyond the map edge: not loaded

Not client work: a mapped Piccadilly bookshop chosen as an example start.Cannot say: crossing delays, steps, slopes, opening hours, or who actually comes. Not client work; not a complete catchment or a count of residents served: the street frame clips every band. Distances include short unvalidated connectors from each place to the street network. This is reach, not demand.How each layer is known: derived (the 5-minute streets and the 390 m buffer); not known (beyond the frame edge).What I still need to know. Crossings, steps and barriers, which the street network does not record.© OpenStreetMap contributors, ODbL 1.0, retrieved 7 Oct 2026. Walking distances derived on the mapped street network.Inspect: soho-walking-network.json, soho-accessibility-manifest.json, soho-twin.json.Street-based walking times (ODbL 1.0); Buildings, streets, water (ODbL 1.0), retrieved 7 October 2026.

Read the Urban Heat Diagnostic

Plate I · Measure

Plate II · Locate

Plate III · Compare

Plate IV · Measure

Plate V · Compare

Bring a place and a question.