GeoJSON Validator & Fixer
Upload or paste your GeoJSON; find winding order, unclosed ring, coordinate range, duplicate point and self-intersection issues against RFC 7946, and fix the repairable ones with one click.
Your data stays in your browser — nothing is uploaded to a server. All checks run client-side in dependency-free, plain JavaScript.
Related Tools
Online GeoJSON Validator and Geometry Fixer
Catch Geometry Errors Before You Publish
Exported GeoJSON files often carry hidden geometry errors: unclosed polygon rings, winding orders that violate RFC 7946, duplicate points, projected (meter-based) coordinates or self-intersecting rings. These may go unnoticed on a map, yet silently break area calculations, spatial queries and some rendering libraries.
- Comprehensive Checks: JSON syntax, type fields, coordinate range, ring closure, winding order, duplicate points, short rings, self-intersection
- Severity Levels: Findings are classified as error / warning / info and reported with their location
- Auto Repair: Rings are closed, winding orders flipped, duplicate points removed
- Change Summary: How many rings were closed, windings flipped and points removed — all reported
How to Use
Upload your GeoJSON file or paste its content. Click "Validate" to get the findings list; every row carries a severity icon, the location of the issue and an explanation. "Auto Repair" fixes the repairable issues in one step, re-validates the repaired data and makes it available for download/copy together with a change summary. Issues that cannot be fixed safely, such as self-intersections, are only reported.
Other Tools
Format your validated data with the GeoJSON Formatter and inspect it visually with the Map Viewer.
Frequently Asked Questions
Why does winding order matter?
The GeoJSON standard, RFC 7946, requires polygon exterior rings to be ordered counter-clockwise (CCW) and interior rings (holes) clockwise (CW). Wrong winding order can make polygons render inside-out, fill in holes or produce negative areas in some libraries (e.g. Mapbox GL, D3, some server-side processors). This tool detects the direction using the signed area and fixes it with one click.
Which errors are repaired automatically?
The Auto Repair button safely applies three fixes: it closes unclosed rings (the first point is appended to the end), flips winding orders to comply with RFC 7946 (exterior CCW, interior CW) and removes consecutive duplicate points. Invalid JSON syntax, missing 'type' fields, out-of-range (projected) coordinates and self-intersections are not auto-repaired; they are reported in the findings list.
Why are self-intersections not auto-repaired?
A self-intersecting ring (e.g. a bow-tie polygon) has no single correct fix: the geometry could be split into two polygons, a node could be inserted at the crossing, or the overshooting part could be discarded. Which one is right depends on the intent of whoever produced the data, and an automatic choice could silently corrupt it. That is why the tool reports self-intersections with their location and leaves the fix to you in a GIS package such as QGIS.