WKT Geometry Viewer

Parse and visualize Well-Known Text (WKT) geometry strings on an interactive map.

Tested tool guide Tested browser tools Checked August 16, 2026

What WKT Geometry Viewer does, with a checked example

This tool reads a WKT (Well-Known Text) string - POINT, LINESTRING, POLYGON, or one of their MULTI/GEOMETRYCOLLECTION variants - and draws it as a vector overlay on an interactive slippy map, auto-zooming to fit the geometry's extent. Parsing runs as you type or paste, so a typo shows up immediately as a failed render rather than a silent blank map. The most common surprise: WKT orders coordinates as X Y, meaning longitude before latitude, the opposite of how people usually read GPS coordinates aloud - pasting lat/lon pairs plots everything mirrored or out in the ocean.

Worked example

A concrete input and expected output from the current implementation.

Input

POINT(-122.4194 37.7749)

Expected output

A single marker appears at 37.7749 N, 122.4194 W - San Francisco, CA - with the map centered and zoomed to that point.

WKT gives coordinates as X Y, meaning longitude then latitude, so -122.4194 is read as longitude and 37.7749 as latitude.

How the result is produced

Parsing

The input text is matched against the WKT grammar for each supported type - POINT, LINESTRING, POLYGON, and their MULTI/GEOMETRYCOLLECTION forms - extracting coordinate pairs from the nested parentheses. A syntax error such as unbalanced parentheses, a missing comma, or an unrecognized keyword stops the parse and reports it rather than guessing at intent.

Rendering and fit

Valid geometry is converted into map overlay shapes - points as markers, lines and rings as vector paths - and the map viewport is automatically fit to the geometry's bounding box, so a single point centers and zooms in while a large polygon zooms out to show the whole shape.

Good uses

Pasting a WKT value copied from a PostGIS or spatial SQL query result to see where it actually falls on the map
Sanity-checking a geometry before inserting it into a GIS database, to confirm the coordinate order and shape are correct
Visualizing a WKT string included in an API response or bug report without opening a full desktop GIS application

Limits and checks

No CRS/SRID handling: coordinates are plotted as plain longitude/latitude (WGS84); WKT in a projected system like Web Mercator meters will plot at the wrong location or off the visible map with no warning.
Coordinate order is easy to get backwards: WKT is X Y (lon, lat); pasting a lat/lon pair copied from Google Maps or a GPS device silently plots the geometry in the wrong place rather than raising an error.
Malformed input fails rather than auto-corrects: a missing closing parenthesis, a stray comma, or a geometry keyword outside the expected dialect can stop the parse instead of rendering a best-effort shape.

Common questions

What geometry types does it accept?

The standard WKT types defined by the OGC Simple Feature Access specification: POINT, LINESTRING, POLYGON, MULTIPOINT, MULTILINESTRING, MULTIPOLYGON, and GEOMETRYCOLLECTION. Anything outside that grammar, such as curved-geometry extensions, will not parse.

Is the WKT text I paste sent anywhere?

No. Parsing and rendering happen in the browser; the tool does not upload the geometry to a server, so it works with data you would not want to paste into an external mapping service.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.