GIS Tools: WKT, WKB, GeoJSON, H3 Converter with Mapping & Spatial Analysis

No. Every conversion runs as JavaScript inside your browser, so the geometry you paste, draw or import never leaves your device and is never stored by us. The page does make network requests, and it is worth knowing which: its own code, map tiles from OpenStreetMap, which reveal the area you are looking at but not the shapes on it, and analytics and advertising scripts that load only after you accept cookies. Share links work the same way: your layers are compressed into the part of the URL after the # symbol, and browsers never send that part to a server.

The converters move between WKT, WKB in hexadecimal, GeoJSON, H3 cell indexes and plain latitude/longitude pairs, in any direction. File export covers six formats: GeoJSON, WKT, WKB, KML, CSV and GPX. File import currently reads GeoJSON, WKT and WKB; KML, GPX and CSV import is not available yet, and the app says so rather than failing quietly. The geometry types supported throughout are Point, MultiPoint, LineString, MultiLineString, Polygon, MultiPolygon and GeometryCollection.

They are two encodings of the same OGC Simple Features geometry model, so converting between them loses nothing. WKT is text you can read: POINT (34.7654 32.0853). WKB is the same geometry in binary, shown here as hexadecimal. WKB is smaller, faster to parse and free of the rounding that writing decimals as text can introduce, which is why spatial databases such as PostGIS store it. WKT is the one to reach for when you need to read, diff or paste a geometry by hand.

Longitude first, in all three. POINT (34.7654 32.0853) means longitude 34.7654 and latitude 32.0853, and RFC 7946 defines a GeoJSON position as [longitude, latitude]. The exception on this page is the Lat/Lon converter, which expects latitude first because that is the order GPS receivers and mapping apps display; tick its invert option when your input is longitude first. A point that lands in the wrong part of the world is nearly always this swap.

Because one of its coordinates fell outside the valid range: longitude must be between -180 and 180, and latitude between -90 and 90. The usual cause is panning sideways. A web map repeats the world endlessly and longitude keeps counting upward as you go, so a shape drawn one copy of the world east of Israel comes out at longitude 394.7654 instead of 34.7654. Values like that are rejected or misplaced by most GIS software, so the shape is refused rather than quietly moved on your behalf; pan back to the main copy of the map and draw it again. A latitude beyond the poles almost always means longitude and latitude have been swapped.

Not in every case, and the app tells you when something is left out. GPX describes waypoints, routes and tracks, so it has no way to represent a polygon, and polygons are omitted from a GPX file. The KML export writes the outer ring of each polygon, so interior rings, meaning holes, are not carried across. Whenever either happens a warning names what was dropped and which formats would have kept it. GeoJSON, WKT, WKB and CSV preserve every geometry type this tool supports.

A circle drawn on the map is stored as a 64-sided polygon, because WKT, WKB and GeoJSON have no circle primitive; every format that appears to support circles does something similar. The polygon is inscribed in the true circle, so its area comes out roughly 0.1 to 0.3 per cent small. The vertices are placed with a local flat-earth approximation, which is accurate at ordinary radii but drifts for very large circles and close to the poles. That is fine for visualisation and for most analysis, but if you need an exact circular area, calculate it from the centre and radius rather than from the exported polygon.

H3 is a global grid, developed by Uber, that divides the world into hexagonal cells, each identified by a short index such as 8a2a1072b59ffff. It is widely used to group point data into cells of comparable size. All sixteen resolutions are supported, from 0, the coarsest, to 15, the finest, and in both directions: paste an H3 index to draw its cell boundary on the map, or give a latitude, longitude and resolution to get the index of the cell that contains that point. The batch dialog converts many indexes at once.

There is no account and no sign-up, and the tools are free to use in any current browser on desktop or mobile. Once the page has loaded, converting, drawing, editing and exporting keep working without a connection; the OpenStreetMap background tiles will not load, but your geometry still displays and converts. The spatial analysis tools are the exception, because they fetch the Turf.js library from a CDN the first time you run one, so they need a connection at least once per session.