Geo Reprojection & Repair Workbench
The repair half of a diagnose-then-fix loop that starts with the Geo QA & CRS Inspector: that tool finds a missing .prj, an out-of-range coordinate, an unclosed ring, or wrong winding order — this tool fixes exactly those. Reprojection: pick a UTM zone (every one of its 120 zones is computed from a formula, no EPSG registry needed) or paste a WKT/proj4 CRS definition — exactly what a working .prj file already contains — and every coordinate converts to WGS84 using the same logic the Shapefile import path relies on. Geometry repair only ever applies provably lossless fixes automatically: closing an unclosed ring, and reversing a ring's winding direction. Removing a feature with too few points to be valid geometry is the one operation that deletes data, so it's opt-in and shows exactly how many features it would affect first. The original file is never modified; a repaired copy exports in any of the five formats. Nothing is uploaded; everything runs in your browser.
Nothing is uploaded — everything runs directly in your browser.
About this tool
This tool is the repair half of a diagnose-then-fix loop that starts with the Geo QA & CRS Inspector: that tool finds a missing or unreadable .prj, an out-of-range coordinate, an unclosed polygon ring, or a ring wound the wrong direction — this tool fixes exactly those. Reprojection handles the CRS-shaped problems: pick a UTM zone (every one of its 120 zones is computed from a formula, not looked up in a registry, so there's no EPSG database to maintain or get out of date) or paste a full WKT/proj4 CRS definition — exactly the same text a working .prj file already contains — and every coordinate is converted to WGS84 using the same reprojection logic the Shapefile import path already relies on. Geometry repair handles the structural problems, and only ever applies fixes that are provably lossless: closing an unclosed ring appends a point that exactly repeats one already there, and reversing a ring's winding direction changes how it's traced without changing what shape it traces — neither can make a valid geometry represent something different than it already did. The one operation that isn't lossless — removing a feature whose line or ring has too few points to mean anything — is opt-in and shows exactly how many features it would affect before you turn it on. Your original file is never modified; a repaired copy is generated for download in whichever of the five export formats you choose. Nothing is uploaded; everything happens in your browser.
What you can do
- Manually reproject a file's coordinates to WGS84 — pick a UTM zone, or paste a WKT/proj4 definition
- Fixes exactly what the Geo QA & CRS Inspector flags: unclosed rings, wrong winding order
- Every automatic fix is lossless — nothing is deleted unless you explicitly turn that on
- Nothing is uploaded — the file is read, repaired, and exported entirely in your browser
How to use
Step 1
Pick a file, and a CRS if it needs one
Default is "already WGS84" — override only if the Geo QA & CRS Inspector flagged out-of-range coordinates.
Step 2
Geometry repair runs automatically
Unclosed rings are closed and wrong winding order is reversed — both lossless, no opt-in needed.
Step 3
Review, then export
Optionally remove features with too few points to be valid, then download the repaired file in any format.
Example
A repair looks like this:
REPAIR.WINDING_FIXED
Feature #7: reversed 1 ring wound the wrong direction.
That ring still traces exactly the same shape — only the direction it's listed in changed, which is what RFC 7946 §3.1.6 requires and some stricter GeoJSON consumers actually check.
How your data is handled
This tool is labeled 🟢 Browser: your file is read directly via your browser's File API, and every reprojection and repair runs entirely client-side — nothing is uploaded, and there's no server involved anywhere in this tool. No AI model is used; every fix is a deterministic, explainable rule.
Frequently asked questions
How do I know if I need to reproject anything?+
Run the Geo QA & CRS Inspector first — a GEO.CRS_MISSING or GEO.COORDINATE_OUT_OF_RANGE finding there means this tool's reprojection step is the fix. If your file passes clean, there's nothing to reproject and the default "already WGS84" setting is correct.
I don't know my file's exact EPSG code — can I still fix it?+
If it's UTM (the most common projected CRS by far), you only need the zone number and hemisphere, not an EPSG code — the tool computes the full projection definition itself. For anything else, search the CRS name or EPSG code on a site like epsg.io or spatialreference.org and copy its WKT or proj4 text (not just the number) into the custom definition field.
Why do ring-closing and winding fixes happen automatically, with no option to turn them off?+
Because both are strictly lossless — closing a ring adds a point that exactly repeats one already there, and reversing winding order doesn't move a single coordinate, only the direction they're listed in. Neither can produce a "wrong" result the way a judgment call could, so there's nothing to opt into.
Why isn't an antimeridian crossing or an out-of-range coordinate fixed automatically?+
An antimeridian crossing needs an actual splitting algorithm to fix correctly — a mechanical rule risks producing an incorrect shape, so it isn't attempted. An out-of-range coordinate usually isn't a geometry bug at all — it's a CRS problem, and reprojecting with the correct source CRS (the other half of this tool) is the real fix, not clamping or guessing at a corrected value.
Does this modify my original file?+
No — your file is only ever read. Every fix produces a new, separate file you choose to download; nothing is changed in place.