Ozarks From Above

Elevation is streamed as 256×256 PNG tiles from the AWS Open Data Terrain Tiles dataset (originally produced by Mapzen, sourced from USGS 3DEP lidar and SRTM). Each pixel encodes a height in Terrarium format:

elevation_m = (R × 256 + G + B / 256) − 32768

MapLibre GL (the open-source fork of Mapbox GL JS) decodes those tiles into a height mesh on the GPU and drapes public-domain USGS National Map aerial imagery over it. No API keys, no usage caps, no tracking — every byte comes from an open government or open-data endpoint. The dawn/dusk buttons just move the hillshade’s sun and tint the sky — same data, different hour.

Each destination is a saved camera: center, zoom, pitch, and bearing, hand-tuned so valleys read as valleys (low and up-valley, pitch 60–70°) and lakes read as maps (high oblique). The tour chains MapLibre’s flyTo, which flies a zoom-out-then-in arc along the great circle between camera positions — the same easing van Wijk & Nuij published in their 2003 paper on smooth and efficient zooming. The compass in the corner is live: it reads the camera’s actual bearing, eye altitude, and the terrain elevation under the crosshair every frame.

The relief slider multiplies every height before the mesh is built. The Ozarks are old, worn mountains — at 1× they are honest; at 2.5× they are how they feel when you’re driving them.

Same reason as the living logo: most of what looks like magic is public data plus a few hundred lines of glue. Streaming-tile terrain rendering was a PhD-grade problem in 2005. Today it’s an open-source library and an open S3 bucket. The gap between “we could never build that” and “that shipped on a Tuesday” is almost always smaller than it looks — that’s the whole pitch.