Spatial Data Types
Points, lines and polygons in SQL.
What Is Spatial Data?
Spatial data describes real-world locations, shapes, and areas. Unlike a plain number or string, a spatial value carries geometric meaning — a point on a map, a road segment, or the boundary of a country.
PostGIS is a PostgreSQL extension that adds powerful spatial data types and functions, turning your database into a full geographic information system (GIS).
-- Enable the PostGIS extension
CREATE EXTENSION IF NOT EXISTS postgis;The GEOMETRY Type
The core spatial type in PostGIS is geometry. It stores shapes in a flat (Euclidean) coordinate space. You can specify a subtype such as POINT, LINESTRING, or POLYGON as a constraint when creating a column.
Specifying the SRID (Spatial Reference ID) alongside the subtype tells PostGIS which coordinate system your data uses.
CREATE TABLE locations (
id SERIAL PRIMARY KEY,
name TEXT,
geom geometry(POINT, 4326)
);