Piers Cowburn, liquid cities from Google Earth data

What it is, and who made it

Renders of London (Westminster and the Thames) and Shibuya in which streets and buildings bend along smooth curves, as if the city were a liquid surface. Three stills and a 24 s clip.

Parts, layer by layer

• Source layer: Google Earth photogrammetry meshes with baked facade textures (O, from the post).
• Deformation field: smooth, large-scale; rows of buildings follow it like streamlines (O). In the clip the camera drifts with mean speed 0.092 widths per second, coherence 0.41 (M).
• Texture: where the field shears, facade pixels stretch into streaks (O). Measured stretch share (structure-tensor coherence over 0.6) 0.16 to 0.29 across the stills (M).
• Bend: 3.5 to 4.1 degrees per 1% of width (M); controls 2.7 to 6.6 (hand-drawn shelves, Bayer ribbons, Elettrosumma blocks, Moran canyon). The measure does not separate this work: a reported null.
• Light: photoreal daylight render; shadows follow the bent geometry (O).

The framework behind it

Advection applied to solid geometry: positions move through a velocity field while topology is kept. The look comes from two rules: deform vertices smoothly, and do not resample textures, so they stretch where the field stretches.

The same idea in distant fields

• Geology: folded strata; rock flows over long times and the layers record the strain.
• Glaciology: flow bands in glaciers.
• Cartography: cartograms and fisheye maps bend a city for a reason (population, attention).
• Film: the city-folding scene in Inception (from memory, a reference to check, not this work's source).

Dual edge

Bending a real city is a strong image of instability. Used on a news surface it could imply damage that did not happen. The data has a licence (Google Earth terms) that limits reuse; our version should use open map data.

Measured

Concepts

• advection
• attention
• block cube
• checking as craft
• city architecture
• code
• data
• field
• glitch datamosh
• grain texture
• layering
• light
• light direction
• line hatching
• network graph
• noise as signal
• ribbon
• scale crop
• stone sand
• stratification
• tessellation
• time as material
• turbulence
• viscosity
• water

All studies