GeoJSON Viewer

Field guide: GeoJSON Viewer

GeoJSON is the lingua franca of web mapping — every API, every export button, every developer handoff speaks it — but a .geojson file is just text until something draws it. This viewer parses FeatureCollections, Features and bare geometries (Points, LineStrings, Polygons and their Multi- variants), shows you what's inside (feature counts, vertex totals, an attribute table), and renders an instant preview, all without your file leaving the browser.

That privacy point matters more than it sounds: GeoJSON files are routinely customer locations, asset registries or survey data, and the popular 'paste your file here' map sites run your data through their servers. Here parsing is 100% client-side. When you need a real pannable map, one click downloads a self-contained HTML file (Leaflet + OpenStreetMap tiles + your data inlined) you can open, share or host anywhere — your own instant web map.

Field tips

• If nothing renders, check coordinate order: GeoJSON is [longitude, latitude] — reversed coordinates are the #1 cause of features in the ocean.
• Use the attribute table to sanity-check property names before handing data to a developer — casing mismatches break joins silently.
• The HTML download works offline-ish too: tiles need internet, but your data is inlined and never touches a server.

Records are stored only in this browser (localStorage) — export regularly. This tool aids field documentation; it does not replace your agency's official inspection procedures or engineering judgment.