GeoJSON Map Editor
LocalEdit GeoJSON on an interactive map — draw points, lines and polygons, edit attributes, undo/redo, then export. Free in your browser, nothing uploaded.
Shortcuts: Ctrl/⌘+Z undo · Ctrl/⌘+Shift+Z redo. GeoJSON over 5 MB is parsed/serialized in a Web Worker and falls back to the main thread automatically. Malformed input (unclosed rings, string/Infinity/null coordinates, empty coordinate arrays, broken geometry structure) is rejected loudly with the feature number.
Target field = expression. Functions: round(x,d) abs floor ceil min max · text: upper lower trim concat substr replace (literal, no regex) · geometry: length($) in meters, area($) in m². Join strings with concat; missing properties error out instead of silently becoming 0.
Sample data loaded — click Load to try it; edit the input and this note disappears.
MapLibre + OpenStreetMap/CARTO basemaps · draw, edit attributes in the table, calculate fields by expression, undo/redo (Ctrl/⌘+Z, Ctrl/⌘+Shift+Z), snapshots restorable and exportable as GeoJSON — all processed locally in your browser.
What is it? GeoJSON Map Editor views and edits GeoJSON on an interactive MapLibre map: draw points/lines/polygons, edit attributes in the table (multi-select delete, expression field calculator), compare against the original, undo/redo and save named snapshots, then export — locally in your browser, free with no sign-up. For very large files (tens of MB), simplify or decimate the data first for smooth editing.
TL;DR: Draw and edit GeoJSON on an interactive map — undo/redo, snapshots and a field calculator, then export. Free, no sign-in, nothing uploaded.
How to use
- Paste your GeoJSON into the input box (a sample is pre-filled), click "Load" or "Open file" (over 5 MB parses in a Web Worker) — or pause typing and it applies automatically. Very large files (tens of MB) are smoother if you simplify/decimate them first.
- Pick a mode (Browse / Point / Line / Polygon) to draw, or edit attributes in the table below the map; use "Field calc" as target field = expression (applies to selected features only, or all).
- Safety nets: undo/redo (Ctrl/⌘+Z, Ctrl/⌘+Shift+Z, 50 steps) and named snapshots (up to 10, restorable and exportable as GeoJSON).
- Click "Export" to get the updated GeoJSON.
FAQ
Which basemaps are available?
Three vector basemaps — Positron, Dark and Voyager — styled by CARTO on OpenStreetMap data. Basemap tiles are fetched from the map provider.
Is my data uploaded?
No. Your GeoJSON stays in your browser; only basemap tiles are fetched from the map provider.
Can I undo an edit?
Yes. Undo/redo (50 steps) covers loads, table edits, the field calculator and completed draw/vertex-edit sessions (one session = one undo step); shortcuts Ctrl/⌘+Z and Ctrl/⌘+Shift+Z.
What can field-calc expressions do?
Arithmetic with round(x,d)/abs/floor/ceil/min/max, text functions upper/lower/trim/concat/substr/replace, and geometry metrics length($) in meters and area($) in m². Missing properties error out instead of silently becoming 0.
What about very large files?
GeoJSON over 5 MB is parsed/serialized in a Web Worker (falling back to the main thread automatically — both paths run the same function), so the page stays responsive. For very large files (tens of MB), simplify or decimate the data first (e.g. with the GeoJSON Simplify tool) — editing tens of millions of vertices is slow no matter how it is parsed.
Is it free? Do I need an account?
Yes — loading, editing and exporting a GeoJSON uses a free daily allowance and needs no sign-in. Batch processing and larger quotas are the paid Pro tier.
How is this different from geojson.io?
geojson.io is the best-known open-source editor and a good default. This tool runs on MapLibre with local rendering, parses files over 5 MB in a Web Worker, adds 50-step undo/redo, named snapshots and an expression field calculator, and never asks you to sign in or upload. If you currently edit in geojson.io and want those, it is a drop-in alternative.
How do I edit a GeoJSON file?
Paste the file's text and click Load, or click Open file to pick a .geojson/.json — over 5 MB is parsed in a Web Worker. Edit geometry by drawing or moving features, edit attributes in the table below the map, then click Export to download the updated GeoJSON. No QGIS, Excel or desktop GIS needed.
Can I draw new features and export them?
Yes — switch to Point, Line or Polygon mode and draw on the map, fill in attributes in the table, then Export. The drawn features are plain GeoJSON in WGS84 longitude/latitude, ready for any mapper or GIS pipeline.
Is it built on maplibre-gl-draw or mapbox-draw?
Neither — the drawing core is terra-draw (MIT), an actively maintained drawing library that supports MapLibre, Mapbox GL, Leaflet and OpenLayers; here it runs on a MapLibre GL map. If you were looking for a draw plugin to code with, that is the library under the hood; if you just want to draw and export GeoJSON, this tool is the no-code path.
Examples
- Input: paste a GeoJSON FeatureCollection (a sample is pre-filled) and click Load.
- Output: draw or edit features on the map, tweak attributes in the table, then Export the updated GeoJSON.
- Draw a polygon on the map, fill in its attributes in the table, and export a ready-to-use GeoJSON FeatureCollection.
Supported formats
Limitations
- Editing is feature-level (no topological editing).
- Basemaps require network access — the map area you view is visible to the tile provider (CARTO/OpenStreetMap).
- Built on MapLibre GL (BSD-3) and terra-draw (MIT).
- Undo history keeps 50 steps; snapshots keep 10 named entries.
- Exporting an empty feature set is blocked with an amber notice — no empty FeatureCollection download is offered; load or draw at least one feature first.
- Malformed input is rejected loudly with the feature number: unclosed rings, string/Infinity/null coordinates, empty coordinate arrays, and broken geometry structure (previously such input silently reached the map/table).
Privacy
Privacy first: this tool runs entirely in your browser — your input and files never leave your device, and everything is cleared when you close the page.