Overview

From a kilometre of Britain to a 9 cm object

Every plate goes through the same four stages. The first two happen on a computer — turning open survey data into a solid model. The last two happen in the studio — printing it and finishing it by hand.

A finished Sheffield City Centre plate in white PLA on a black graphite base, lit against a dark background, the engraved label reading SHEFFIELD CITY CENTRE and its coordinates. — A finished Sheffield · City Centre plate — one real square kilometre at 1:11000, on its graphite base.

01SurveyAircraft LIDAR for heights; OpenStreetMap for footprints.

02ModelHeights + footprints fused into one watertight mesh.

03PrintSliced into layers and built up in PLA over ~14 hours.

04FinishCleaned by hand, seated on a base, engraved, boxed.

The whole pipeline, start to finish. Each stage is explained below.

Stage 01 · Survey

Measuring a real place

LIDAR — measuring the ground with light

The heights come from LIDAR (light detection and ranging). An aircraft flies a grid over the country firing a laser straight down — hundreds of thousands of pulses a second. Each pulse reflects off whatever it hits, and the time it takes to return gives the height of that point to within a few centimetres.

Millions of returns become a point cloud — then a tidy grid of heights at one-metre spacing.

From a cloud of points to a grid

Raw LIDAR is messy: millions of scattered 3D points, no two evenly spaced. To be useful it’s resampled onto a regular one-metre grid — a height for every square metre, like pixels in an image where the value is elevation rather than colour.

Scattered returns are resampled into one regular height sample per square metre.

What real LIDAR looks like

That is the principle. To see what a real square kilometre of survey data actually looks like — coloured by height, lit as relief, sliced and stood up in three dimensions — see The data behind every map.

Bare earth vs. everything on it

The same scan produces two surfaces. The DSM (digital surface model) keeps everything the laser saw first — roofs, trees, walls. The DTM (digital terrain model) strips those away to leave bare ground. Cityform builds from the surface model, because the buildings are the subject — but the terrain underneath is why a hill still reads as a hill.

Surface model (left) keeps buildings and trees; terrain model (right) is the ground alone.

OpenStreetMap — telling the heights apart

LIDAR knows how tall a thing is, but not what it is — it can’t tell a roof from a hill, or a canal from a road. OpenStreetMap fills that in: an open, community-drawn map where every building, street and waterway is a tagged shape. Every footprint you see was traced by a volunteer somewhere. I use it to decide which parts of the grid are buildings to raise and which are water to cut down.

A finished Cityform plate with a magnifying glass. — The finished plate — every street and waterway traced from open survey data.

Open data

Both datasets are public. Britain’s public bodies release their LIDAR under the Open Government Licence — the Environment Agency in England, the Scottish Remote Sensing Portal in Scotland, and Natural Resources Wales in Wales; OpenStreetMap is an open database built by volunteers. Cityform is only possible because that survey work is shared — so the attribution travels with every plate. More in Reference →

Why it matters

Measured ground, not a flat slab

Most free 3D map tools extrude building outlines to a guessed height and drop them on a flat base. Cityform sets the same streets on the real ground — the rise to a ridge, the fall to a river, the height of each block, all measured from the air. Below is the same square kilometre of Sheffield, from one camera. Drag the slider to compare: the only thing that changes is the data beneath it.

The same square kilometre of Sheffield built as a Cityform model on Environment Agency LIDAR terrain, the streets and blocks rising and falling with the measured ground.

The same square kilometre as flat OpenStreetMap building footprints extruded to tagged heights on a level base.

OpenStreetMap only Cityform · LIDAR

Drag to compare

The same 1 km² of Sheffield city centre, from one camera. Left of the line: OpenStreetMap footprints on a flat base. Right: the Cityform model on measured LIDAR terrain. Same streets — the difference is the ground beneath them.

Two more things the survey carries

A Sheffield street grid as a Cityform model: the roads sit as shallow grooves engraved into the relief, on measured terrain. — **Roads, engraved as grooves**Drag across: on the Cityform side the streets are cut as shallow grooves into the relief, so the grid reads without raising walls that aren’t there. Sheffield city centre.

The same street grid as OpenStreetMap building blocks on a flat base, with no engraved roads or terrain. — **Roads, engraved as grooves**Drag across: on the Cityform side the streets are cut as shallow grooves into the relief, so the grid reads without raising walls that aren’t there. Sheffield city centre.

Whitby harbour as a Cityform model: the River Esk, harbour and sea are cut hollow below the land, with the two piers reaching out. — **Water, cut hollow**Drag across: the harbour and the River Esk are sunk below the surface rather than filled flat, so water reads as water, not pavement. Whitby.

The same view as OpenStreetMap building blocks on a flat base, with the water filled flat and no piers. — **Water, cut hollow**Drag across: the harbour and the River Esk are sunk below the surface rather than filled flat, so water reads as water, not pavement. Whitby.

Stage 02 · Model

Turning data into a printable solid

A printer can’t read a height grid or a map. It needs a single watertight mesh — a closed surface with no gaps or holes, so the software can tell exactly what is solid and what is air. A model with a hole in it is like a bucket with a hole: the slicer doesn’t know where to stop.

The grid of heights is closed into one sealed surface — the model the printer reads.

So I take a 1 km × 1 km crop, drape the OpenStreetMap footprints over the LIDAR height field, raise the buildings to their surveyed heights, cut the rivers and docks below the surface so a confluence reads as water rather than pavement, and seal the whole thing into one solid block sat on its base.

Built to print

Because the plate is one continuous solid, anything that would hang in mid-air is filled in for strength. A bridge prints as a solid deck joined to the ground on each bank — the open span beneath it, and the cables or piers that would hold a real one, are closed in rather than left floating. Fine features like railings or a single narrow footbridge can merge into the surface. The footprint and position stay true to the survey; it’s only the unsupported structure underneath that’s solidified, so the model holds together in the hand and in the post.

Stage 03 · Print

How the printing works

The plates are made by FDM — fused deposition modelling, the most common kind of 3D printing. A spool of PLA is fed into a hot nozzle, melted, and laid down as a fine thread. The printer draws the model one flat slice at a time; each slice cools and sets, and the next is laid on top. Enough slices and a flat drawing becomes a solid object.

Slicing — turning a model into instructions

Before anything prints, software slices the 3D model into hundreds of horizontal layers and works out the path the nozzle must trace for each one. That path — every move and squirt of plastic — is what the machine actually follows.

Each slice becomes a path the nozzle traces, bottom to top.

Why the layer height matters

The thickness of each slice — the layer height — is the resolution. At 0.16 mm a ridge line, a viaduct or a railway cutting keeps its edge instead of blurring into a block. Thinner layers mean more detail and more time; 0.16 mm is the balance I’ve settled on, and a plate takes about 14 hours on a Bambu Lab machine.

Each pass adds one layer. Build up enough and a flat drawing becomes solid terrain.

Terrain helps: a city surface rises gradually rather than overhanging, so it mostly supports itself as it prints — no scaffolding to cut away afterwards, which keeps the finish clean.

A printed Sheffield plate on a brushed-metal surface, showing the matte white PLA relief at a three-quarter angle. — The printed surface in matte white PLA — every block built up from ~0.16 mm layers.

Materials

What it’s made of

Each plate is printed in white PLA. PLA (polylactic acid) is a rigid plastic made from fermented plant sugar — corn or sugarcane — rather than crude oil. It prints sharply, holds fine detail, and reads as a clean matte white rather than a shiny plastic.

It is worth knowing where that plastic begins. PLA starts in a field rather than an oil well: plant sugar from corn or sugarcane is fermented into lactic acid, and that acid is joined into long chains and drawn into filament. So the white relief on the plate began as a crop — a renewable material rather than a petroleum one.

PLA is made from fermented plant sugar — corn or sugarcane — not crude oil: the sugar becomes lactic acid, which is spun into filament and printed as the matte white relief.

Why PLA, and not resin or PETG

Resin prints can be finer, but they’re brittle, can keep yellowing in light, and the process is messy and fume-heavy — wrong for an object meant to live in daylight on a shelf for years. PETG is genuinely tougher and far more heat- and UV-resistant — the better choice for something handled often or kept outdoors. It just prints glossier and fussier at sub-millimetre relief, where PLA’s matte, dimensionally sharp surface wins. For a piece that lives indoors on a shelf, PLA’s strengths are the ones that count.

Each plastic is strong somewhere. For an indoor piece with fine matte relief, PLA’s strengths line up — while PETG is tougher and far more heat- and UV-resistant, which matters more for parts handled often or kept outdoors.

Good to know

The one thing PLA doesn’t like is heat — it softens well above room temperature, so the only place to avoid is a sunny windowsill or a radiator shelf. Indoors and out of direct sun, it lasts indefinitely.

The city sits on a separate graphite base (white on request), which carries the weight and frames the print the way a plinth frames a model.

A Sheffield plate on natural linen, showing the soft matte texture of the white PLA against the black base. — Matte white PLA on a graphite base — no gloss, no glare.

Stage 04 · Finish

From print to object

Off the printer, each plate is checked, cleaned up by hand, and seated on its base. A stainless-steel label is laser-engraved with the city name and its exact coordinates and set into the front — so even though individual houses are too small to resolve, the plate is precisely located.

Then it’s packed in a custom box and posted from Sheffield, usually within 7 working days for England (around 14 days for Wales and most of Scotland). One person, one kilometre at a time.

Put together, the work after the print leaves the bed runs in four steps, each done by hand:

The four studio steps after the print comes off the bed — the same shape as the four-stage overview at the top of the page.

Macro close-up of the engraved label reading SHEFFIELD CITY CENTRE 53.381 degrees N 1.470 degrees W on the ribbed black base. — The laser-engraved label — city and exact coordinates — set into the front of the base.

And those coordinates place it exactly. Read the latitude and longitude off the label, find them on any map, and you land in the middle of the very kilometre the plate shows.

A map of Great Britain with Sheffield marked by a pin joined to a label reading SHEFFIELD, 53.380 degrees North, 1.464 degrees West — the coordinates engraved on the plate. — The coordinates on the steel label aren’t decoration — they fix each plate to one exact point on the map of Britain.

Scale & detail

What 1:11000 means

1:11000 is the scale — the model is 11,000 times smaller than the real place. One centimetre on the plate is 110 metres on the ground, so the whole 9 × 9 cm plate holds a square kilometre. At that size a football pitch is about a centimetre across — and a house is under a millimetre. So the plate shows you the shape of a place, not its front doors.

A Sheffield plate seen from directly above, showing a whole kilometre of streets and blocks in fine white relief. — From directly above: a whole kilometre of streets and blocks in fine relief. Individual buildings are sub-millimetre — you read the pattern, not the front doors.

What you’ll recognise

The street and block pattern
The river, canal or coastline
Hills, valleys, how the ground falls
Major landmarks and large buildings

What you won’t pick out

Individual houses, doors or windows
House numbers, signs or your car
Anything much smaller than a metre

The finished object — in millimetres

The map crop is nine centimetres square, but the object you hold is a little larger: a 105 × 105 mm base, 17 mm deep, with the white relief rising on top. The relief height changes from city to city — flat centres sit low, hilly ones stand taller — so the total height varies. A removable stainless-steel label carries the city name and coordinates.

Every Cityform sits on a 105 mm square base, 17 mm deep. The relief on top adds the rest — its height set by the city’s own terrain, so total height varies. The steel label lifts out of its holder.

Why one kilometre, at nine centimetres

A square kilometre is about the size of a place you actually know on foot — a town centre, the walk to the station, the streets around a childhood home. Smaller and you lose the context; larger and the detail shrinks past reading. At 9 cm the result sits in the hand and on a shelf, close enough to find one terrace, wide enough to read a whole centre.

What the survey can’t show

It’s built from real data, but data has edges. Worth knowing before you order:

New buildings lag. If something went up after the last survey, it may be missing or shown as the site that was there before.
Trees are simplified. Canopy reads as soft mass, not individual branches.
Coverage has gaps. LIDAR is thinner near the edges of Welsh and Scottish coverage; a few squares come back flat or as water.
Every order is checked. If a chosen kilometre can’t be produced to spec, you hear within 48 hours — full refund, or the nearest workable square.

Reference

Open data & a short glossary

Cityform stands on public survey work. Two open datasets do the heavy lifting, and both ask that their attribution travels with anything made from them — so it’s on the box, the listing, and the footer of this site.

Public-sector LIDAR — open terrain and surface heights from the Environment Agency (England), the Scottish Remote Sensing Portal (Scotland) and Natural Resources Wales (Wales), all licensed under the Open Government Licence. OpenStreetMap — community-mapped footprints for buildings, roads and water, under the ODbL. Open data is the whole reason a one-person studio can make a faithful model of anywhere in Britain.

Coverage is not even across the country — see the national map on The data behind every map.

The two datasets behind every plate
Dataset	What it provides	Accuracy	Licence
Public-sector LIDAR	Ground and surface heights, measured from aircraft — Environment Agency (England), Scottish Remote Sensing Portal, Natural Resources Wales	To a few centimetres vertically	Open Government Licence v3.0
OpenStreetMap	Building footprints, roads, and water	Community-mapped vector data	ODbL

LIDAR: Light detection and ranging — measuring distance (and so height) by timing laser pulses.
Point cloud: The raw scan: millions of scattered 3D points, before they’re tidied into a grid.
DTM / DSM: Digital terrain model (bare ground) vs. digital surface model (ground plus buildings and trees).
Mesh: A 3D surface made of joined triangles. It must be “watertight” — fully sealed — to print.
FDM: Fused deposition modelling: building an object by laying down melted plastic in layers.
Slicing: Converting a 3D model into the layer-by-layer paths the printer follows.
PLA: A rigid plastic made from plant sugar; the matte white the plates are printed in.

Commission your kilometre →

Practical questions — durability, base colours, lead times — are answered on the Studio page.
Heights from public-sector LIDAR — Environment Agency (England), Scottish Remote Sensing Portal (Scotland) and Natural Resources Wales (Wales) — licensed under the Open Government Licence v3.0. Footprints © OpenStreetMap contributors, licensed under the ODbL.