WKT Validator — free & private
Paste WKT or upload a .wkt/.txt file. Validate Polygon/MultiPolygon rings, holes, duplicates, self-intersections, and get anti-meridian hints with a live map preview.
FAQ
Does this upload my WKT?
No. Everything runs locally in your browser. Nothing is sent to a server.
What WKT inputs do you accept?
Single WKT geometry, GeometryCollection, or multiple WKTs (one per line). You can also upload .wkt or .txt files.
What does the validator actually do with my input?
It parses your WKT and normalizes it into a GeoJSON FeatureCollection. If you provide multiple geometries, they’re handled as multiple features and can export back as a GeometryCollection or one-WKT-per-feature.
What issues are checked?
Polygon/MultiPolygon deep checks include: ring closure, minimum vertices (≥4 when closed), zero-area rings, holes outside their outer ring (error), holes touching the outer boundary (warning), self-intersections (error), duplicate ring pairs (warning), and RFC 7946 winding hints. Across ALL geometry types it also checks non-finite coordinates (error) and lon/lat out-of-range (warning, assuming WGS84).
Why do I see an “anti-meridian” warning?
If the validator detects longitude jumps >180°, the geometry likely crosses the anti-meridian (±180°). That can make ring winding checks and fixes unreliable unless you split the polygon first.
Which geometry types are supported?
Polygon and MultiPolygon get full ring/hole validation + fixes. Other types (Point/LineString/etc.) are still parsed and included, but only basic coordinate checks are applied.
Can I fix problems here?
Yes—conservative fixes are available: close rings, remove consecutive duplicate vertices, drop zero-area rings, enforce RFC 7946 winding (disabled when anti-meridian crossing is likely), and drop duplicate rings (holes) within a polygon.
Will “Fixes” solve self-intersections or holes outside the polygon?
No. Those are topology problems that usually require proper geometry repair. The validator flags them, but only applies safe, deterministic edits (closure/dedup/zero-area/winding/duplicate rings).
Why do I still get output even when there are errors?
Errors mean the geometry is invalid by common rules, but we still show a normalized output so you can inspect it, export it, or try conservative fixes. A hard failure only happens when nothing valid can be parsed at all.
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