A free, open-source geospatial platform providing global elevation data, interactive maps, and geospatial APIs — powered by NASA SRTM 30m data and served on Cloudflare's global edge network.
OpenZenith exists to make elevation and geospatial data accessible to everyone. No API keys, no rate limits on basic queries, no paywalls. Whether you're building a hiking app, researching terrain, or just curious about the elevation where you stand — the data is free and fast.
Single-point and batch elevation queries. Bilinear interpolation for smooth results from NASA SRTM 30m DEM tiles.
Full-featured map with multiple basemaps, hillshade layer, 3D terrain, pins with elevation data, and shareable URLs.
CesiumJS-powered 3D globe with real-time data overlays: earthquakes, flights, satellites, natural events, and weather.
Multi-tab data explorer with NOAA, USGS, Celestrak, OpenSky, ArcGIS, Overpass/OSM, and marine weather integrations.
The platform is built with modern, lightweight tools:
Elevation data comes from NASA's Shuttle Radar Topography Mission (SRTM) at 30-meter resolution, stored as OZT1-compressed tiles on Cloudflare R2. Additional real-time data is proxied from:
Real-time and historical earthquake feeds with magnitude, depth, and GeoJSON geometry.
Real-time ADS-B flight tracking with position, altitude, speed, and callsign data.
Satellite TLE data for active, visual, communication, navigation, and weather satellites.
Natural event tracking: wildfires, volcanoes, icebergs, landslides, and severe storms.
Weather warnings, forecasts, and marine conditions via the National Weather Service.
Marine weather API: wave height, direction, period, wind speed, and temperature.
Creator & maintainer of OpenZenith. Full-stack developer with a passion for geospatial data, open-source software, and making elevation data freely accessible.
Converted NASA SRTM HGT files into OZT1-compressed terrain tiles, optimized for edge delivery via Cloudflare R2.
Built the elevation API on Cloudflare Edge Runtime with bilinear interpolation, tile caching, and CORS-free access.
Added a full-featured MapLibre GL map with hillshade, 3D terrain, multiple basemaps, and elevation pin queries.
Integrated CesiumJS for a 3D globe with real-time overlays: earthquakes, flights, satellites, and natural events.
Built a multi-tab data explorer integrating NOAA, USGS, Celestrak, OpenSky, ArcGIS, and Overpass API.
Expanded with shared components, quality infrastructure (ESLint, Prettier, Vitest), and comprehensive API documentation.
OpenZenith is open source under the MIT license. Contributions are welcome — whether it's new data sources, bug fixes, feature requests, or documentation improvements. Visit the Contribute page to learn how to submit data or open a pull request.
This project is licensed under the MIT License. Elevation data is sourced from NASA SRTM, which is public domain.