WKT (Well-Known Text)
May 25,2026

GISBox is a one-stop 3D GIS data editing, conversion and publishing platform that supports editing in multiple GIS formats such as OSGB/GEOTIFF/RVT, converting to 3DTiles/Terrain and publishing.

Introduction

WKT (Well-Known Text) is a standardized text format used to represent geometric objects—such as points, lines, and polygons—in a human‑readable string form. It is widely applied in geographic information systems (GIS) and spatial databases. For example, POINT(30 10) represents a point with coordinates (30, 10); LINESTRING(0 0, 1 1, 2 1) represents a polyline; and POLYGON((0 0, 10 0, 10 10, 0 10, 0 0)) represents a rectangular polygon. Its syntax is defined by the Open Geospatial Consortium (OGC), facilitating the exchange of spatial data between different systems.

File Structure

The file structure of WKT, defined by the OGC standard, can be summarized in the following hierarchical elements:

Basic geometry types: The fundamental building blocks, including POINT, LINESTRING, and POLYGON, used to represent discrete locations, linear paths, and closed areas respectively.
Multi‑geometry types: Used to aggregate multiple geometries of the same type for batch representation, including MULTIPOINT, MULTILINESTRING, and MULTIPOLYGON.
Composite geometry structure: GEOMETRYCOLLECTION can mix arbitrary combinations of geometry objects (points, lines, polygons, etc.) to enable unified representation of heterogeneous spatial data.
Coordinate dimension extension: Supports 2D, 3D, and 4D coordinate systems by appending dimension type suffixes.
Spatial Reference System Identifier (SRID): The extended format EWKT (Extended WKT) allows embedding the SRID directly, specifying the coordinate system.
Empty object representation: Supports the EMPTY keyword to declare a geometry object with no content, representing missing or invalid geometries.

Pros

High human readability: Uses plain text with an intuitive syntax (e.g., POINT(30 10)), making it easy for developers to debug, manually edit, and quickly understand geometric structures, significantly lowering the learning and maintenance threshold.
High cross‑platform compatibility: Natively supported by major GIS systems (e.g., PostGIS, QGIS, ArcGIS) and spatial databases. It serves as a common intermediate format for data import/export and interoperation between systems, enabling seamless integration.
Supports multidimensional extensions: Can represent 2D, 3D (Z), and 4D (ZM) coordinates, supports empty geometry objects (e.g., POINT EMPTY), and composite structures (GEOMETRYCOLLECTION), meeting complex spatial modeling needs.
Acts as a conversion bridge: Often used as an intermediate carrier for converting geometries between formats such as GeoJSON, WKB, and Shapefile, enabling standardized transfer of geometric data among heterogeneous systems.

Cons

Low storage and transmission efficiency: Textual redundancy results in a much larger volume than the binary WKB format. For the same geometry, WKT files are typically 3–5 times larger than WKB, increasing network bandwidth and storage overhead.
High parsing performance cost: Text parsing requires character‑by‑character matching and syntactic analysis, consuming significantly more CPU compared to WKB’s direct memory mapping. This becomes a performance bottleneck in high‑frequency query or real‑time streaming scenarios.
No attribute support: Describes only the geometric shape, without any attribute fields (e.g., name, type, timestamp). An additional structure (such as GeoJSON) is required, limiting its independence for expressing complete features.
Lack of built‑in indexing mechanism: Does not natively support spatial indexing. Query efficiency depends entirely on the underlying database (e.g., PostGIS’s R‑tree), which can lead to full table scans on large datasets, affecting response times.
Limited projection description capability: The WKT1 version has insufficient ability to express complex coordinate systems (e.g., compound projections, time dimensions). Although the WKT2 standard improves this, its adoption remains low, and most practical systems still use the simplified version.

Application Scenario

As the OGC‑standard text format for geometry representation, WKT is widely used in GIS and spatial databases as a common exchange language for spatial objects such as points, lines, and polygons.

Example

1. Vue + OpenLayers: Reading WKT data and displaying graphics.

2. All WKT data types are based on point data. The X and Y values of point coordinates are separated by spaces, and coordinates are separated by commas.