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CSV to GeoJSON Converter - Online Map Data Generator

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CSV to GeoJSON Converter

Transform spreadsheet coordinates into map-ready GeoJSON — supports Points, LineStrings & Polygons

CSV Input
Paste CSV or upload a file to begin
Configuration
Parse CSV data first to see available columns
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GeoJSON Output
Data Preview (first 15 rows)
Parse CSV data to see preview
Frequently Asked Questions
What is GeoJSON and why should I use it?

GeoJSON is an open standard format for encoding geographic data structures. It's widely supported by mapping libraries (Leaflet, Mapbox, Google Maps), GIS software (QGIS, ArcGIS), and databases (PostgreSQL+PostGIS, MongoDB). Converting CSV to GeoJSON bridges the gap between spreadsheet data and interactive maps, enabling you to visualize points, routes, and regions instantly.

What coordinate order does GeoJSON use?

GeoJSON strictly uses [longitude, latitude] order — not [latitude, longitude]. Longitude comes first (X-axis, -180 to 180), followed by latitude (Y-axis, -90 to 90). This is the same order used in most GIS systems (EPSG:4326). Our tool automatically arranges coordinates correctly based on your column selections, so you don't need to worry about this.

How do I handle GPS tracks (LineString) with multiple routes?

Use the Group By Column option. If your CSV has a column like track_id or route_name, rows sharing the same value will be combined into a single LineString. Use the Sort By Column option (e.g., a timestamp or sequence number) to ensure points appear in the correct order along the route.

Does the tool automatically close Polygon rings?

Yes! If the first and last coordinates of a polygon group don't match, the tool automatically appends the first coordinate to close the ring. This ensures your polygons render correctly in all GeoJSON-compatible viewers. You'll see a note in the conversion summary when auto-closure is applied.

What happens to rows with invalid coordinates?

Rows where longitude or latitude values are missing, non-numeric, or out of range (lon: -180~180, lat: -90~90) are skipped during conversion. The tool reports how many rows were skipped in the conversion summary. We recommend cleaning your data before conversion to avoid unexpected results.

Can I preview my GeoJSON on a map before downloading?

Absolutely! Copy the generated GeoJSON and paste it into geojson.io — a free online map viewer that renders GeoJSON instantly. You can also drag & drop the downloaded .geojson file directly onto the map. For larger datasets, try mapshaper.org.

What's the maximum file size I can convert?

This tool runs entirely in your browser — there's no server-side processing. It can comfortably handle CSVs with up to 50,000 rows on most devices. For very large datasets, consider splitting your CSV into smaller chunks or using command-line tools like ogr2ogr (GDAL) or csv2geojson (Node.js).

How do I add elevation (Z) values to my GeoJSON?

If your CSV includes an elevation/altitude column, include it in the Properties selection. However, GeoJSON geometry coordinates can optionally include a third value for elevation: [longitude, latitude, elevation]. Our current version stores elevation in properties. For 3D coordinates in the geometry itself, you may need post-processing with a script.

Why are some of my features missing after conversion?

Common reasons: (1) The group has too few points — LineStrings need ≥2 points, Polygons need ≥3 distinct points. (2) Coordinates are invalid or out of range. (3) The row contains empty coordinate values. Check the conversion warnings for details on skipped groups and rows.

Can I use this tool offline?

Yes! Once the page loads, all processing happens locally in your browser. No data is ever sent to any server. You can even save the page for offline use — your CSV data stays private and secure on your device.