> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cockroachlabs.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Well Known Text

The Well Known Text format (hereafter *WKT*) provides a text representation of a geometric shape.  It can be used to:

* Build instances of various shapes (e.g., using `ST_MakePolygon` on a Linestring).
* Convert existing shapes to a text representation for ease of reading.

Each shape in WKT has a *tag* which says what it is, usually followed by a list of coordinates.  For example, here are some common tags:

* `POINT(...)`
* `LINESTRING(...)`
* `POLYGON((...))`

WKT is technically case insensitive, but is sometimes displayed using "CamelCase" for easier reading.  For example, one can represent a MultiPolygon as either of:

* `MULTIPOLYGON(...)`
* `MultiPolygon(...)`

When a shape is made up of homogeneous subcomponents, such as a polygon made up of various points, the subcomponents do not need to have their own tags. For example:

`LINESTRING(-88.243385 40.116421, -87.906471 43.038902, -95.992775 36.153980)`

Shapes expressed in WKT can have an [SRID](https://docs.cockroachlabs.com/docs/stable/architecture/glossary.md) prepended to the shape and followed by a semicolon, in the form `SRID=123;TAG(...)`.  The format is known as Extended Well Known Text (*EWKT*); it is the same as WKT, with an [SRID](https://docs.cockroachlabs.com/docs/stable/architecture/glossary.md#srid) representation prepended to the data structure.

For example, below is a polygon representing a geometry that uses [SRID 4326](https://docs.cockroachlabs.com/docs/stable/srid-4326.md), which is used to represent latitude and longitude coordinates on the Earth as defined in the [WGS84](https://docs.cockroachlabs.com/docs/stable/architecture/glossary.md#wgs84) standard:

`SRID=4326;POLYGON((-87.906471 43.038902, -95.992775 36.153980, -75.704722 36.076944, -87.906471 43.038902))`

> [!NOTE]
>
> For more detailed information about the Well Known Text format, see [the OGC specification for WKT](http://docs.opengeospatial.org/is/18-010r7/18-010r7.html).

> [!NOTE]
>
> CockroachDB only supports 2-dimensional geometries.

## See also

* [Spatial Data Overview](https://docs.cockroachlabs.com/docs/stable/spatial-data-overview.md)
* [Spatial indexes](https://docs.cockroachlabs.com/docs/stable/spatial-indexes.md)
* [Spatial and GIS Glossary of Terms](https://docs.cockroachlabs.com/docs/stable/architecture/glossary.md)
* [Geographic information — Well-known text representation of coordinate reference systems](http://www.opengis.net/doc/is/wkt-crs/2.0.6)
* [OpenGIS Implementation Specification for Geographic information - Simple feature access - Part 1: Common architecture](https://portal.opengeospatial.org/files/?artifact_id=25355)
* [Well known binary](https://docs.cockroachlabs.com/docs/stable/well-known-binary.md)
* [GeoJSON](https://docs.cockroachlabs.com/docs/stable/geojson.md)
* [SRID 4326 - longitude and latitude](https://docs.cockroachlabs.com/docs/stable/srid-4326.md)
* [Introducing Distributed Spatial Data in CockroachDB](https://www.cockroachlabs.com/blog/spatial-data/) (blog post)