3D Map Explainer — Style Prompt

Real elevation and real imagery built into a three-dimensional map with the vertical exaggerated, lit by one warm, low sun; a sea coloured by its real depth; and over it a layer of data that glows, flows and lights up along true geography: routes, lanes, measurements, pillars. One camera falls from space into the place, flies over it, cuts it open, and climbs back out. References (grammar only): news organisations' 3D terrain explainers (a dive from the whole region to the point that matters, then back out); documentary aerials in low raking light (relief stood up by its shadows); nautical charts (lanes, separation zones, soundings, title blocks). Copy none of their colours, icons, typefaces or camera paths; never name them in the film.

1. Essence, and what it is not

• The ground is real data. Elevation and bathymetry from public tiles, imagery from licence-clean satellite mosaics, coastlines and place names where they really are. Nothing on the ground is invented or traced; whatever is drawn (a route, a pipeline path) is labelled schematic.
• Two layers. The terrain says what this place is like; the glowing layer says what happens here. The data layer is the only thing that glows.
• Relief stands up. Heights are exaggerated (about ×3 for land, stated on screen) and lit by a low sun, so mountains read even from orbit.
• The data layer advances. Each time it appears it does one more thing than before: flow, structure, depth, volume, alternatives, the whole world.
• One camera, one world. Globe, region and close-up are the same place at different heights; moving between them is a camera move or a dissolve through the atmosphere, never a cut to a different map.

Not Satellite Briefing (grey analyst imagery seen straight down, hairline measurements), not Transit Map (an abstract diagram), not Isometric Infographic or Low-poly Island (no stylised diorama), not Sci-fi Hologram HUD (no invented chrome, no wireframe terrain), not a slide deck over a map (no header bars, centred blocks or page turns).

2. Materials & rendering

• Terrain: one mesh per level of detail (a detailed grid for the place, a coarser one for the region; the coarse one discards itself under the fine one with a small overlap and is lowered a few tens of metres so the seam never fights). Imagery as albedo, graded warm with a little less saturation and a little more contrast; a roughness map from the land–sea mask, so the sea has a soft sheen and land is matte.
• The sea: not the imagery's colour. Shade it by real depth: coastal shallows keep a little of the imagery's texture toned teal, deep water goes to navy. Distances along the coast are measured in kilometres, so every zoom level shades alike.
• Sun and shadows: one directional sun about 20° high, a weak sky/ground hemisphere fill. Shadows are baked into textures (march toward the sun over the height grid, penumbra widening with distance to the occluder) and multiplied into the direct light; shadow maps shimmer when a camera flies over hundreds of kilometres.
• The glowing layer: additive ribbons, not tone-mapped, so only they trigger bloom. Width = the larger of a real width and a minimum in pixels (computed per vertex from the distance to the camera): routes stay 2–3 px from orbit, a lane or a road keeps its true width up close. One shader serves draw-on (reveal), a bright travelling head, flowing pulses, dashed boundaries and wakes or trails behind traffic.
• Lines on land (pipelines, borders): the glowing line sits on a dark casing in normal blending, the way charts print a cased line; on bright desert a glow alone washes out.
• Traffic (ships, trains, trucks, planes): flat warm-white glyphs with a short fading wake or trail, scaled to stay about the same size on screen at any height; offset a little inside their lane so they never sit on the bright centre line.
• Data pillars: stacked slabs, one slab per unit, each with a lit rim; they grow slab by slab where the quantity belongs. A comparison stands side by side, on the same scale, on open ground or water, seen square-on.
• The cross-section: cut the map along a meaningful line (the narrowest point, a border, a river); the camera side of the terrain is swept away in about a second and a wall shows the profile: water at real depth times a stated factor (×100–200), a bright surface line, a faint contour every 25 m, a warm sea-floor line and finely striated rock below.
• The globe: the same imagery on a sphere (a whole-Earth mosaic plus the regional imagery laid over its own area), a thin Fresnel rim of atmosphere, a dark star field, the night side in shadow. During a dissolve the globe camera is computed from the map camera (latitude, longitude, height, north up) so the two line up.
• Post: physical depth of field with the focus on the subject and the aperture proportional to distance (it deepens smoothly as the camera descends), bloom on the glowing layer, a warm grade and vignette, 2× supersampling.
• 2D overlay for all type and measurements, positioned every frame through one world → screen function.

3. Colour logic

• Neutral ground: the place's own colours, warmed. No colour ramps over the terrain.
• Amber is data (routes, lanes, the main quantity). Cool white is boundaries (lane edges, limits). Warm white is what moves and what measures (traffic, rulers, the measured line). A second data hue (a teal) appears only when a quantity is compared against the main one; a range is the same hue one step lighter.
• Type on land is dark brown ink, type on water pale sea blue, type on dark shadowed mountains warm white. No outlines, no drop shadows.
• The sea's navy and the night side of the globe are the only large dark areas.

Example (our demo): deep sea #0E2230, shallows #1F5A5C, sand highlight #E8D2A6, data amber #FFA63D / core #FFC36B, boundaries #D9E6EE, traffic #F4E6CF, rulers and the measured line #F6EEE0, land ink #2B2119, sea type #BCDBE6, comparison teal #2FA3B0 / range #8FD6DE.

4. Type & subtitles

• A condensed grotesk for everything Latin (e.g. Barlow Condensed, OFL): country names 600 at ~30 px with wide tracking (≈ 0.3 em); sea names 500 at ~21 px, pale blue; island and port names 15 px; data numbers 600 at 70–96 px with a small unit and a smaller source line beside or under them. A CJK sans (e.g. Noto Sans SC, OFL, subset to the characters used) for Chinese, ≥ 34 px.
• Labels sit on the map where the thing is, and fade with the camera's height: a far set (countries, seas) hands over to a near set (islands, ports). A label the frame would cut fades out instead.
• Measurements are drawn, then labelled: a line grows from its middle to both ends, end ticks snap on, then the label appears beside the line, never on the data.
• A cross-section is labelled like an engineering drawing: a small caption and a headline in the upper left, the exaggeration factors under them, a depth scale on the side, dashed soundings from the surface to the floor with their value.
• Title: a pin on the place, a ring pulse, a leader line to the title set in empty space (sea, sky); English with one short Chinese line under it.
• Subtitles (when the film is spoken): a map-legend shelf at the bottom left, an amber vertical rule, one Chinese line over one English line, never wrapped, on a soft dark gradient floor; map labels keep out of that area.
• Sources: one small line in a corner for the whole film (data, imagery licence, OSM ODbL if used, "routes schematic", the vertical exaggeration).

5. Motion quality

• The camera never stops dead: distance interpolates in log space, keys are monotone cubic, holds keep a slow drift.
• The glowing layer arrives by being drawn: lines grow from their source, a lane ignites with a bright head running along its real course, pulses flow in the direction of travel, pillars grow slab by slab on the beat.
• Depth of field, fog and bloom change continuously with height; nothing pops.
• Traffic moves at a time-lapse speed that reads (a few km per film second), all in its lanes.
• Frame rate and grain: 24 fps; mux grain 1, a light film grain.

6. Camera grammar

Transitions: dissolves through the atmosphere (globe ↔ map, with the cameras matched), the cut that opens the ground, one rhythmic hard cut at most, everything else continuous. At key moments the subject fills a third of the frame; subtitles bottom left; sources in a corner.

7. Sound palette

• Score: low plucked strings for a pulse, cello spiccato when things move, bowed vibraphone and harp for light and air, hand chimes or glockenspiel for each thing that lights up, frame drum on downbeats, a horn swell under a quantity; a low sine pedal with 2nd and 3rd harmonics. Avoid the generic piano-and-strings bed.
• Foley: thin high-altitude air that thickens as the camera comes down, a whoosh for each dive, small data ticks for terminals and rulers, a sub thump and an electric shimmer when a lane ignites, a low tearing sweep for the cut, a muffled undersea hush inside a cross-section, the sea under low shots, one pizzicato per pillar slab.
• Silence: under the cross-section the music thins to a pedal; before a verdict, half a bar of nothing.
• Mix: narration compressed and ~10 dB (RMS) over the music; the music bus dips 300 Hz–4 kHz and ducks under each line; −14 LUFS, true peak ≤ −1 dB.

8. Native moves

• The dive from orbit. One push from the globe into the place, a dissolve through the atmosphere where the globe and the map share one camera. Fits content like: any place that matters to the world; a city in a country; a reef in an ocean.
• Flows converge. Points light up and their routes grow and pour into one line. Fits content like: commuters into a city centre; tributaries into a river; roads into a pass.
• A line ignites along its true course. A bright head runs along the real geometry and leaves the line, its boundaries and its traffic behind. Fits content like: a rail line; a border; a pipeline; a migration route.
• Cut the map open. Sweep away one side of the terrain along a line and show the profile underneath. Fits content like: the depth of a lake; a river valley; a tunnel under a mountain; an aquifer.
• Fly the line. A low tracking shot along it, a ruler across it. Fits content like: a bridge's span; a canal; a runway; a front line.
• Quantities on the ground. A pillar grows where the quantity belongs, and its alternatives grow beside it on the same scale. Fits content like: a river's yearly discharge; a dam's output; harvests by region.
• Back to the world. Pull out to the globe, the data layer still glowing. Fits content like: where things go next; who depends on this place.

Our demo opens on the dive from orbit, uses cut the map open and quantities on the ground as its turns and ends back to the world. A new film opens and ends another way: a close, low shot that climbs to reveal the region, a single glowing point on a dark region, an ending on a last quantity held over the place, or the cross-section closing back into the map.

9. Pitfalls of the medium

• Licences: Sentinel-2 cloudless by EOX is CC BY 4.0 only for the 2016 release (later releases are CC BY-NC-SA); AWS Terrain Tiles (SRTM, GMTED, ETOPO1, GEBCO) are free with attribution; OSM data is ODbL (credit and share-alike for the database): name the terms to the user before using it. Not usable: Google Earth/Maps, Bing, Esri World Imagery, Mapbox Satellite, Maxar, Planet, news photos, AI-generated imagery as ground. Log every download (URL, date) and put the credit line in the picture.
• Facts: every number on screen and in the narration needs a named source and a stated basis (whose estimate, which year, what is counted); when sources disagree, show both and say whose is whose. Keep them in FACTS.md. Schematic things (routes, simplified pipelines) are labelled as such on screen.
• Resolution: z10 terrain is ~150 m per cell; very close flights look soft, small islands are missing (mark them with a dot, do not invent them). Fetch finer data only for the area the camera will really approach.
• Mercator vs sphere: the flat map is Web Mercator, the globe is a sphere; matching a dissolve needs the camera converted, not hand-placed, and the dissolve kept short (≈ 0.8 s).
• Shimmer: no real-time shadow maps over large flights; no lines under ~2 px; no thin dashes from orbit (fade dashes out with distance).
• Sun glint: a camera that looks toward a low sun over water gets a large specular blob that blooms; keep the sea's roughness high enough, or look away from the sun.
• Glow close to the lens: a pillar or a lane right in front of the camera blooms into a blob; start growth after the camera has risen, or lower bloom with distance.
• Comparisons: a small quantity in a pale colour on bright terrain disappears; use a solid contrasting hue, the same scale, a clean background and number labels as large as the main one, and hold ≥ 2.5 s.
• Borders and place names: imagery and terrain carry no borders; draw none unless the film is about them. Labels and any border data follow DIRECTOR.md §13.
• Ribbons are double-sided: a flat ribbon whose side vector flips loses its faces to back-face culling.

10. Engine

• demo/index.html: the demo's whole film on one timeline (its strait, ships and pipelines are the demo's subject; your film maps its own): terrain meshes with baked shadows, the ribbon shader, ships, the cross-section wall, pillars, pipelines, the globe and its routes, both camera tracks and the globe ↔ map conversion, the 2D overlay (labels, measurements, rulers, subtitles, end card).
• demo/post.js: physical depth of field, bloom, grade (a copy of core/three/post.js).
• demo/tools/: fetch.py, fetch_wide.py, fetch_world.py (tiles), prep.py, prep_wide.py (height grids, graded albedo, depth-shaded sea, water masks), bake.py (low-sun shadows), fonts.py, cues.py.
• Extra packages: none; the data tools use the standard library, numpy, SciPy and Pillow from the library's venv.

11. Variation space

The agent decides the place, the question, the data layers and their order, the camera path, the exaggeration factors and whether there is narration.

• Structures: a funnel (world → region → point → back out); a journey along one line (a river from source to sea); two places compared on one scale; a before/after on the same terrain.
• Openings: the globe; a close, low shot that climbs to reveal the region; a single glowing point on a dark region.
• Endings: back to the globe; a last quantity held over the place; the cross-section closing back into the map.

How our demo was made (story, shots, score, end card, build): DEMO.md. Read it after your treatment exists.