WKT Viewer & Converter

Paste WKT or GeoJSON and see the geometry drawn instantly — points, lines, polygons, and every MULTI* type. Read its bounding box and centroid, and convert WKT ⇄ GeoJSON with one click. Everything runs in your browser; nothing is uploaded.

How to use the WKT viewer

Paste a geometry into the box on the left. The viewer auto-detects whether it is WKT (or PostGIS EWKT with a SRID=…; prefix) or GeoJSON, parses it, and draws it on the right — points as dots, lines as strokes, and polygons filled and outlined, with interior rings cut out as holes. Below the picture you get a stats line: the geometry type, vertex count, bounding box, and centroid. Use the Input format selector to force a format if auto-detection guesses wrong, and the Load example buttons to see a polygon, a line, a multipolygon, or a curved geometry rendered immediately.

The map is a simple fit-to-data planar projection with a light coordinate grid — it shows the shape and relative positions of your geometry, not a georeferenced street map. That keeps the tool fully self-contained: there are no tile servers and no map libraries, so nothing you paste ever leaves your browser.

What formats are supported

• WKT geometry types — POINT, LINESTRING, POLYGON, MULTIPOINT, MULTILINESTRING, MULTIPOLYGON, and GEOMETRYCOLLECTION. Optional Z/M ordinates are read and ignored for the 2-D drawing.
• EWKT SRID prefix — a leading SRID=4326; is parsed, shown in the stats line, and preserved when you copy back to WKT.
• GeoJSON — a bare geometry, a Feature, or a FeatureCollection (folded into a GEOMETRYCOLLECTION when converting to WKT).
• Curved geometry — CircularString, CompoundCurve, CurvePolygon, MultiCurve, and MultiSurface are detected and drawn approximated as straight segments between control points, with a heads-up note. The tool does not re-fit true arcs.

WKT vs GeoJSON at a glance

• Coordinate order — both put longitude before latitude. WKT writes a point as x y (space-separated); GeoJSON writes [x, y]. This tool keeps the order intact through the round trip. (One wrinkle: SQL Server stores geography latitude-first in its own type — the Jam SQL Studio desktop app normalizes that on decode, so the WKT it shows and copies is standard longitude-latitude.)
• Where they show up — WKT is what relational databases speak (PostGIS ST_AsText, SQL Server .STAsText(), Oracle SDO_UTIL.TO_WKTGEOMETRY); GeoJSON is what web maps and JavaScript expect.
• Curves — WKT can express true arcs (CircularString); GeoJSON has no arc primitive, so this tool converts a curve to a plain line through its control points. That is why converting a curve to GeoJSON is inherently an approximation.

Frequently asked questions

What is WKT (Well-Known Text)?

Well-Known Text is a plain-text way to describe vector geometry — for example POINT (30 10), LINESTRING (30 10, 10 30, 40 40), or POLYGON ((35 10, 45 45, 15 40, 35 10)). It is defined by the OGC Simple Features standard and is understood by PostGIS, MySQL, SQL Server, Oracle Spatial, and SpatiaLite. Coordinates are written x y (longitude latitude for geographic data), and an optional SRID=4326; prefix names the coordinate system.

How do I convert WKT to GeoJSON (and back)?

Paste WKT into the viewer above and click Copy as GeoJSON — the tool parses the geometry and emits an equivalent GeoJSON object. Paste GeoJSON instead and click Copy as WKT to go the other way. The converter maps POINT/LINESTRING/POLYGON and all the MULTI* types plus GEOMETRYCOLLECTION to their GeoJSON equivalents, so the round trip preserves the shape. Everything runs in your browser.

Does this tool support MULTIPOLYGON and GEOMETRYCOLLECTION?

Yes. It parses POINT, LINESTRING, POLYGON, MULTIPOINT, MULTILINESTRING, MULTIPOLYGON, and GEOMETRYCOLLECTION, in both WKT and GeoJSON, and draws every part on the same canvas. Polygon holes (interior rings) are rendered correctly with an even-odd fill, and a GEOMETRYCOLLECTION can mix points, lines, and polygons in one value.

What does the SRID=4326; prefix mean?

SRID is a Spatial Reference System Identifier — a numeric code for the coordinate system the numbers are expressed in. SRID 4326 is WGS 84, the longitude/latitude system used by GPS. The SRID=4326;POINT (…) form is Extended WKT (EWKT), how PostGIS labels a geometry's coordinate system. This viewer reads and preserves the SRID prefix; it draws everything with a simple fit-to-data planar projection, so the picture shows the shape rather than a georeferenced map.

Are curved geometries like CircularString supported?

The viewer detects CircularString, CompoundCurve, CurvePolygon, MultiCurve, and MultiSurface and draws them approximated as straight segments between their control points, with a note that the arcs are approximated. It does not re-fit true arcs. The Jam SQL Studio desktop app goes further: it linearizes curves smoothly for display on a real map while keeping the copied WKT exactly curved, on PostgreSQL, Oracle, SQLite, and SQL Server (MySQL has no curve types).

Is my geometry data uploaded anywhere?

No. The viewer is plain JavaScript running entirely in your browser — parsing, drawing, and conversion all happen locally, with no tile servers and no map libraries loaded. The page makes no network requests with your data; you can disconnect from the internet after it loads and it keeps working.

Want this on your live database?

Jam SQL Studio is a free desktop SQL client for PostgreSQL/PostGIS, MySQL, SQL Server, Oracle, and SQLite. It decodes geometry and geography columns straight from the connection and renders them as interactive maps — in the results grid, a peek popover, a Query Editor Map view, a Table Explorer map pane, and a dedicated Spatial Explorer workspace. An optional street basemap is on by default and can be switched off for a fully offline planar view, and curved geometry is linearized for display while your copied WKT stays exactly curved.

Free for personal use • No account required • Mac, Windows, Linux

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