GeoSpatial Functions Reference

StarTree Cloud provides a comprehensive set of geospatial functions that follow the SQL/MM specification with the ST_ prefix. These functions enable you to create, manipulate, measure, and analyze spatial data.

Function Categories

Constructors

Create geospatial objects from coordinates, WKT, WKB, and GeoJSON

Measurements

Calculate distances, areas, and geometric properties

Relationships

Test spatial relationships like containment and intersection

Outputs

Convert geospatial objects to various formats

Conversions

Transform between geometry and geography types

Aggregations

Combine multiple geometries into collections

Constructors

Functions for creating geospatial objects from various input formats.

ST_Point

Creates a point geometry from X,Y coordinates.

ST_Point(double x, double y) → Point

Examples:

-- Create San Francisco point
SELECT ST_Point(-122.4194, 37.7749) as sf_point;

-- Use in query to find nearby locations
SELECT store_name 
FROM stores 
WHERE ST_Distance(location, ST_Point(-122.4194, 37.7749)) < 1000;

ST_GeomFromText

Creates geometry from Well-Known Text (WKT) representation.

ST_GeomFromText(String wkt) → Geometry

Examples:

-- Create various geometry types
SELECT ST_GeomFromText('POINT(-122.4194 37.7749)') as point_geom;
SELECT ST_GeomFromText('LINESTRING(-122.4194 37.7749, -122.4094 37.7849)') as line_geom;
SELECT ST_GeomFromText('POLYGON((-122.5 37.7, -122.4 37.7, -122.4 37.8, -122.5 37.8, -122.5 37.7))') as poly_geom;

ST_GeomFromWKB

Creates geometry from Well-Known Binary (WKB) representation.

ST_GeomFromWKB(bytes wkb) → Geometry

Examples:

-- Create geometry from stored WKB data
SELECT ST_GeomFromWKB(wkb_column) FROM spatial_table;

-- Round-trip conversion
SELECT ST_GeomFromWKB(ST_AsBinary(ST_Point(-122.4194, 37.7749)));

ST_Polygon

Creates a polygon geometry from WKT representation.

ST_Polygon(String wkt) → Polygon

Examples:

-- Create a simple rectangle
SELECT ST_Polygon('POLYGON((-122.5 37.7, -122.4 37.7, -122.4 37.8, -122.5 37.8, -122.5 37.7))');

-- Use in spatial queries
SELECT * FROM locations 
WHERE ST_Within(point_column, ST_Polygon('POLYGON((bounds))'));

ST_GeogFromText

Creates geography from Well-Known Text with spherical calculations.

ST_GeogFromText(String wkt) → Geography

Examples:

-- Create geography for accurate distance calculations
SELECT ST_GeogFromText('POINT(-122.4194 37.7749)') as sf_geography;

-- Use with ST_Distance for meter-based results
SELECT ST_Distance(
  ST_GeogFromText('POINT(-122.4194 37.7749)'),
  ST_GeogFromText('POINT(-74.0060 40.7128)')
) as nyc_to_sf_meters;

ST_GeogFromWKB

Creates geography from Well-Known Binary representation.

ST_GeogFromWKB(bytes wkb) → Geography

Examples:

-- Create geography from WKB data
SELECT ST_GeogFromWKB(wkb_geography_column) FROM geo_table;

ST_GeomFromGeoJson

Creates geometry from GeoJSON string.

ST_GeomFromGeoJson(string geojson) → Geometry

Examples:

-- Create point from GeoJSON
SELECT ST_GeomFromGeoJson('{"type":"Point","coordinates":[-122.4194,37.7749]}');

-- Create polygon from GeoJSON
SELECT ST_GeomFromGeoJson('{
  "type":"Polygon",
  "coordinates":[[
    [-122.5,37.7],[-122.4,37.7],[-122.4,37.8],[-122.5,37.8],[-122.5,37.7]
  ]]
}');

-- Handle Feature objects
SELECT ST_GeomFromGeoJson('{"type":"Feature","geometry":{"type":"Point","coordinates":[-122.4194,37.7749]}}');

ST_GeogFromGeoJson

Creates geography from GeoJSON string.

ST_GeogFromGeoJson(string geojson) → Geography

Examples:

-- Create geography for accurate calculations
SELECT ST_GeogFromGeoJson('{"type":"Point","coordinates":[-122.4194,37.7749]}');

-- Use in distance calculations
SELECT ST_Distance(
  location_geography,
  ST_GeogFromGeoJson('{"type":"Point","coordinates":[-122.4194,37.7749]}')
) as distance_meters FROM stores;

Measurements

Functions for calculating spatial measurements and properties.

ST_Distance

Calculates distance between two geometries or geographies.

ST_Distance(Geometry/Geography g1, Geometry/Geography g2) → double

For Geometry: Returns 2D Cartesian distance in coordinate units
For Geography: Returns great-circle distance in meters Examples:

-- Distance in coordinate units (geometry)
SELECT ST_Distance(
  ST_GeomFromText('POINT(-122.4194 37.7749)'),
  ST_GeomFromText('POINT(-74.0060 40.7128)')
) as coordinate_distance;

-- Distance in meters (geography)
SELECT ST_Distance(
  ST_GeogFromText('POINT(-122.4194 37.7749)'),
  ST_GeogFromText('POINT(-74.0060 40.7128)')
) as meters_distance;

-- Find nearby stores (indexed query)
SELECT store_name, address
FROM stores 
WHERE ST_Distance(location, ST_Point(-122.4194, 37.7749)) < 5000
ORDER BY ST_Distance(location, ST_Point(-122.4194, 37.7749));

ST_Area

Calculates the area of a geometry or geography.

ST_Area(Geometry/Geography g) → double

For Geometry: Returns 2D Euclidean area in coordinate units²
For Geography: Returns area in square meters using spherical model Examples:

-- Area of a polygon in coordinate units²
SELECT ST_Area(ST_GeomFromText('POLYGON((-122.5 37.7, -122.4 37.7, -122.4 37.8, -122.5 37.8, -122.5 37.7))'));

-- Area in square meters using geography
SELECT ST_Area(ST_GeogFromText('POLYGON((-122.5 37.7, -122.4 37.7, -122.4 37.8, -122.5 37.8, -122.5 37.7))'));

-- Calculate area of all regions
SELECT region_name, ST_Area(boundary_geography) as area_sqm 
FROM geographic_regions 
ORDER BY area_sqm DESC;

ST_GeometryType

Returns the type of a geometry as a string.

ST_GeometryType(Geometry g) → String

Examples:

-- Identify geometry types
SELECT ST_GeometryType(ST_Point(-122.4194, 37.7749));  -- Returns: ST_Point
SELECT ST_GeometryType(ST_GeomFromText('LINESTRING(0 0, 1 1)'));  -- Returns: ST_LineString
SELECT ST_GeometryType(ST_GeomFromText('POLYGON((0 0, 1 0, 1 1, 0 1, 0 0))'));  -- Returns: ST_Polygon

-- Filter by geometry type
SELECT * FROM mixed_geometries 
WHERE ST_GeometryType(geom_column) = 'ST_Point';

Relationships

Functions for testing spatial relationships between geometries.

ST_Contains

Tests if the first geometry completely contains the second.

ST_Contains(Geometry/Geography g1, Geometry/Geography g2) → boolean

Returns true if no points of g2 lie outside g1, and at least one interior point of g1 lies in the interior of g2.

Note: ST_Contains on Geography types provides close approximation, not exact results.

Examples:

-- Check if polygon contains points
SELECT COUNT(*) as points_in_region
FROM locations 
WHERE ST_Contains(
  ST_GeomFromText('POLYGON((-122.5 37.7, -122.4 37.7, -122.4 37.8, -122.5 37.8, -122.5 37.7))'),
  location_point
);

-- Find all stores within a delivery zone
SELECT store_name, address
FROM stores 
WHERE ST_Contains(delivery_zone_polygon, store_location);

-- **Index Usage**: First argument must be literal, second must be column
WHERE ST_Contains('<polygon_literal>', point_column)  -- Uses index

ST_Within

Tests if the first geometry is completely within the second.

ST_Within(Geometry/Geography g1, Geometry/Geography g2) → boolean

Returns true if g1 is completely inside g2. Examples:

-- Find points within a region
SELECT location_name 
FROM locations 
WHERE ST_Within(
  location_point,
  ST_GeomFromText('POLYGON((-122.5 37.7, -122.4 37.7, -122.4 37.8, -122.5 37.8, -122.5 37.7))')
);

-- Check if delivery addresses are within service area
SELECT customer_id, address
FROM customers 
WHERE ST_Within(delivery_address, service_boundary);

-- **Index Usage**: First argument must be column, second must be literal
WHERE ST_Within(point_column, '<polygon_literal>')  -- Uses index

ST_Equals

Tests if two geometries represent the same geometry.

ST_Equals(Geometry g1, Geometry g2) → boolean

Examples:

-- Check if two geometries are identical
SELECT ST_Equals(
  ST_GeomFromText('POINT(-122.4194 37.7749)'),
  ST_Point(-122.4194, 37.7749)
);  -- Returns: true

-- Find duplicate locations
SELECT COUNT(*) as duplicate_count
FROM locations l1, locations l2 
WHERE l1.id < l2.id 
  AND ST_Equals(l1.location, l2.location);

Outputs

Functions for converting geospatial objects to various output formats.

ST_AsText

Converts geometry or geography to Well-Known Text (WKT).

ST_AsText(Geometry/Geography g) → string

Examples:

-- Convert geometry to readable text
SELECT ST_AsText(location_column) as wkt_location FROM spatial_data;

-- Debug spatial queries
SELECT store_name, ST_AsText(location) as location_wkt
FROM stores 
WHERE ST_Distance(location, ST_Point(-122.4194, 37.7749)) < 1000;

ST_AsBinary

Converts geometry or geography to Well-Known Binary (WKB).

ST_AsBinary(Geometry/Geography g) → bytes

Examples:

-- Convert to binary format for storage
SELECT ST_AsBinary(location_geom) as wkb_data FROM locations;

-- Export binary data
SELECT id, ST_AsBinary(boundary) as boundary_wkb 
FROM regions 
WHERE region_type = 'administrative';

ST_AsGeoJson

Converts geometry or geography to GeoJSON format.

ST_AsGeoJson(Geometry/Geography g) → string

Examples:

-- Convert point to GeoJSON
SELECT ST_AsGeoJson(ST_Point(-122.4194, 37.7749));
-- Returns: {"type":"Point","coordinates":[-122.4194,37.7749],"crs":{"type":"name","properties":{"name":"EPSG:0"}}}

-- Export data for web applications
SELECT 
  store_name,
  ST_AsGeoJson(location) as geojson_location,
  category
FROM stores 
WHERE city = 'San Francisco';

-- Create GeoJSON FeatureCollection-ready output
SELECT json_object(
  'type', 'Feature',
  'geometry', json(ST_AsGeoJson(location)),
  'properties', json_object('name', store_name, 'category', category)
) as geojson_feature
FROM stores;

Conversions

Functions for converting between geometry and geography types.

toSphericalGeography

Converts a Geometry object to spherical geography.

toSphericalGeography(Geometry g) → Geography

Examples:

-- Convert geometry to geography for accurate distance calculations
SELECT toSphericalGeography(ST_GeomFromText('POINT(-122.4194 37.7749)'));

-- Use in transform functions
"transformFunction": "toSphericalGeography(stPoint(longitude, latitude))"

-- Convert existing geometry column
SELECT 
  location_name,
  ST_Distance(
    toSphericalGeography(geometry_location),
    toSphericalGeography(ST_Point(-122.4194, 37.7749))
  ) as distance_meters
FROM locations;

toGeometry

Converts a spherical geography object to geometry.

toGeometry(Geography g) → Geometry

Examples:

-- Convert geography back to geometry
SELECT toGeometry(geography_column) FROM spatial_data;

-- Use when you need faster calculations over small areas
SELECT location_name
FROM locations 
WHERE ST_Distance(
  toGeometry(geography_location),
  toGeometry(reference_geography)
) < 0.01;  -- Approximate distance in degrees

Aggregations

Functions for combining multiple geometries.

ST_Union

Combines multiple geometries into a single MULTI geometry.

ST_Union(geometry[] g1_array) → Geometry

This aggregate function returns a MULTI geometry or NON-MULTI geometry from a set of geometries. It ignores NULL geometries. Examples:

-- Combine all store locations into a MultiPoint
SELECT ST_Union(ARRAY_AGG(location)) as all_store_locations
FROM stores 
WHERE city = 'San Francisco';

-- Create union of all delivery zones
SELECT region, ST_Union(ARRAY_AGG(delivery_polygon)) as combined_delivery_area
FROM delivery_zones 
GROUP BY region;

-- Combine geometries by category
SELECT 
  store_category,
  ST_AsText(ST_Union(ARRAY_AGG(location))) as combined_locations
FROM stores 
GROUP BY store_category;

Function Usage with Indexes

Functions that Use H3 Index

These functions automatically leverage geospatial indexes when properly configured:

Function	Index Usage	Requirements
`ST_Distance`	FILTER_H3_INDEX	Column as first arg, literal as second, used in range condition
`ST_Within`	INCLUSION_FILTER_H3_INDEX	Column as first arg, literal as second
`ST_Contains`	INCLUSION_FILTER_H3_INDEX	Literal as first arg, column as second

Index-Optimized Query Patterns:

-- These queries use the H3 index:
WHERE ST_Distance(location_column, ST_Point(-122, 37)) < 5000
WHERE ST_Within(location_column, ST_GeomFromText('POLYGON(...)'))  
WHERE ST_Contains(ST_GeomFromText('POLYGON(...)'), location_column)

-- These queries do NOT use the index:
WHERE ST_Distance(ST_Point(-122, 37), location_column) < 5000  -- Arguments reversed
WHERE ST_Within(ST_GeomFromText('POLYGON(...)'), location_column)  -- Arguments reversed

Checking Index Usage

Use EXPLAIN PLAN FOR to verify index usage:

EXPLAIN PLAN FOR 
SELECT * FROM stores 
WHERE ST_Distance(location, ST_Point(-122.4194, 37.7749)) < 5000;

Look for these operators in the query plan:

FILTER_H3_INDEX - ST_Distance queries using index
INCLUSION_FILTER_H3_INDEX - ST_Within/ST_Contains queries using index

Best Practices

Performance Tips

Use geography types for global applications requiring meter-based distances
Use geometry types for regional analysis where coordinate units are acceptable
Index your spatial columns with appropriate H3 resolutions
Structure queries to leverage indexes (proper argument order)

Function Selection Guide

-- For distance-based queries
ST_Distance + geography types = Most accurate
ST_Distance + geometry types = Faster, less accurate over large distances

-- For containment queries  
ST_Within = Point-in-polygon testing
ST_Contains = Polygon-contains-point testing (reverse of ST_Within)

-- For data export
ST_AsGeoJson = Modern web applications
ST_AsText = Debugging and human-readable output
ST_AsBinary = Compact storage and transmission

Get Started

Ingestion

Query Data

Manage Data

Visualize Data

Manage Security

Release Notes

Reference

​Function Categories

Constructors

Measurements

Relationships

Outputs

Conversions

Aggregations

​Constructors

​ST_Point

​ST_GeomFromText

​ST_GeomFromWKB

​ST_Polygon

​ST_GeogFromText

​ST_GeogFromWKB

​ST_GeomFromGeoJson

​ST_GeogFromGeoJson

​Measurements

​ST_Distance

​ST_Area

​ST_GeometryType

​Relationships

​ST_Contains

​ST_Within

​ST_Equals

​Outputs

​ST_AsText

​ST_AsBinary

​ST_AsGeoJson

​Conversions

​toSphericalGeography

​toGeometry

​Aggregations

​ST_Union

​Function Usage with Indexes

​Functions that Use H3 Index

​Checking Index Usage

​Best Practices

​Performance Tips

​Function Selection Guide

Function Categories

Constructors

ST_Point

ST_GeomFromText

ST_GeomFromWKB

ST_Polygon

ST_GeogFromText

ST_GeogFromWKB

ST_GeomFromGeoJson

ST_GeogFromGeoJson

Measurements

ST_Distance

ST_Area

ST_GeometryType

Relationships

ST_Contains

ST_Within

ST_Equals

Outputs

ST_AsText

ST_AsBinary

ST_AsGeoJson

Conversions

toSphericalGeography

toGeometry

Aggregations

ST_Union

Function Usage with Indexes

Functions that Use H3 Index

Checking Index Usage

Best Practices

Performance Tips

Function Selection Guide