GeoJSON Viewer, KML Viewer & GPX Viewer for VS Code

See GeoJSON, KML, KMZ, GPX, shapefiles, TopoJSON, WKT and CSV files on a map inside VS Code. Free, no sign-in, works offline: the basemap ships with the extension and nothing is fetched from the internet.

• Click a feature to see its properties. Open the attribute table, filter it, click a row to zoom there.
• GPX tracks show distance, duration, moving time, elevation gain and an elevation profile.
• Shapefiles are reprojected from their .prj file (UTM, State Plane, Lambert, Albers and more).
• 100 MB files open in a few seconds. Parsing and drawing run in a background worker, so VS Code stays responsive.
• Works in Remote SSH, WSL, Dev Containers and Codespaces: files are read through VS Code, not from a local path.
• Export the current view as a PNG image. Dark and light themes follow VS Code.

Open a file

• .gpx, .kmz, .shp and .topojson open on the map when you click them.
• .geojson, .kml and .wkt open as text, because people edit them. Click the map button in the editor title bar to open the map beside the text. The map redraws while you type.
• Right-click any supported file in the Explorer and pick Open in Map Viewer. This also works for .json (GeoJSON or TopoJSON), .csv and .tsv with latitude and longitude columns, and .zip files that hold a shapefile.
• To always open GeoJSON on the map, add "workbench.editorAssociations": { "*.geojson": "geoMapViewer.mapOption" } to your settings.

What you get

GPX numbers were checked against gpxpy 1.6.2 on a 3-track hike: distance within 0.11%, duration and moving time equal.

Formats

Large files

The file is parsed and packed into typed arrays in a web worker, and the map is drawn on an offscreen canvas. Features smaller than a pixel are drawn as dots and vertices closer than a pixel are skipped, so drawing time follows the screen, not the file. In a test in VS Code 1.142, a 123 MB GeoJSON with 200,000 polygons and 4.1 million vertices showed on the map about 3 seconds after the click (2.9 and 3.1 s in two runs). The editor stayed usable while it loaded: its longest pause was 0.1 to 0.24 s.

Files above 512 MB show a message and are not read. Change the limit with geoMapViewer.maxFileMB.

Privacy and safety

• No network: the webview content security policy allows no remote address, and the basemap is a file inside the extension.
• KML NetworkLinks, remote icons and overlay images are never loaded. The panel tells you how many there were.
• XML entity declarations are removed before a KML or GPX is read, so an entity bomb cannot expand.
• KMZ and ZIP files are unpacked with a size and ratio guard. A zip bomb stops with a message after a fraction of a second.
• Broken coordinates (NaN, latitude beyond 90, text) are left out and counted. The rest of the file still draws.
• No telemetry, no account, no ads.

Settings

Keyboard

Arrow keys pan, + and - zoom, 0 fits all features, F zooms to the selection, B toggles the basemap, T the table, P the panel, Esc clears the selection.

Support Zovo

Zovo extensions are free, with no ads and no tracking. They are made by theluckystrike on GitHub. If this one saves you time, you can support the work:

• Sponsor on GitHub
• Follow theluckystrike on GitHub

More tools by Zovo

• JSONL Viewer, Large JSONL Table & NDJSON Viewer opens JSONL and NDJSON files as a table, as records or as a chat view.
• XLSX Viewer, Excel Viewer, CSV Viewer & Parquet Viewer opens CSV, TSV, Excel and Parquet files as a sortable, filterable table.
• Large JSON Viewer, JSON Browser & JSON Tree shows large JSON files as a searchable tree, copies JSONPath and turns arrays of objects into a table.
• SQLite DB Viewer & SQLite Viewer, Database Viewer (Read-Only) browses SQLite tables read-only and runs SELECT queries.
• NetCDF Viewer & HDF5 Viewer (NC Viewer, H5 Viewer) browses groups, attributes and values in HDF5 and NetCDF files and plots slices.

See all Zovo extensions on the Marketplace.

License

MIT. Bundled libraries and the basemap data are listed in THIRD-PARTY-NOTICES.md.