StarTree Cloud supports comprehensive geospatial data types and formats, enabling you to work with location data in the most appropriate format for your use case.

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Data Type Overview

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Geometry vs Geography

Understanding the difference between geometry and geography types is crucial for choosing the right approach for your spatial data:

Geometry Type

Cartesian Plane Calculations
  • Treats coordinates as X/Y values on a flat surface
  • Distance measurements in coordinate units (often degrees)
  • Best for smaller areas where Earth’s curvature is negligible
  • Faster calculations but less accurate over large distances

Geography Type

Spherical Earth Calculations
  • Accounts for Earth’s curvature in all calculations
  • Distance measurements always in meters
  • More accurate for large distances and areas near poles
  • Slightly slower but geographically correct

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When to Use Each Type

Use CaseRecommended TypeReason
City-wide analysisGeometryFast, sufficient accuracy
Global applicationsGeographyAccurate across all locations
Small regions (< 100km)EitherDifference is minimal
Navigation/GPS dataGeographyRequires precise distances
Engineering/CAD dataGeometryWorking in projected coordinates

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Supported Data Formats

StarTree Cloud supports three industry-standard geospatial formats:

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1. Well-Known Text (WKT)

Human-readable text format that’s easy to understand and debug. Supported WKT Types: 
-- Basic shapes
POINT (longitude latitude)
LINESTRING (x1 y1, x2 y2, x3 y3)
POLYGON ((x1 y1, x2 y2, x3 y3, x1 y1))

-- Multi-geometries  
MULTIPOINT ((x1 y1), (x2 y2))
MULTILINESTRING ((x1 y1, x2 y2), (x3 y3, x4 y4))
MULTIPOLYGON (((x1 y1, x2 y2, x3 y3, x1 y1)), ((x4 y4, x5 y5, x6 y6, x4 y4)))

-- Complex collections
GEOMETRYCOLLECTION(POINT(x1 y1), POLYGON((x2 y2, x3 y3, x4 y4, x2 y2)))
Examples: 
-- San Francisco coordinates
POINT (-122.4194 37.7749)

-- Simple route
LINESTRING (-122.4194 37.7749, -122.4094 37.7849, -122.3994 37.7949)

-- Golden Gate Park boundary (simplified)
POLYGON ((-122.5137 37.7694, -122.4529 37.7694, -122.4529 37.7849, -122.5137 37.7849, -122.5137 37.7694))

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2. Well-Known Binary (WKB)

Compact binary format optimized for storage and transmission. 
-- Create from WKB
SELECT ST_GeomFromWKB(wkb_column) FROM spatial_data;

-- Convert to WKB for storage
SELECT ST_AsBinary(ST_Point(-122.4194, 37.7749));

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3. GeoJSON Format

NEW: Full GeoJSON support for modern web applications and APIs. Supported GeoJSON Types:
  • Point, LineString, Polygon
  • MultiPoint, MultiLineString, MultiPolygon
  • GeometryCollection
  • Feature, FeatureCollection

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GeoJSON Functions

FunctionPurposeExample
ST_GeomFromGeoJson(string)Create geometry from GeoJSONConvert GeoJSON to internal format
ST_GeogFromGeoJson(string)Create geography from GeoJSONSame but with spherical calculations
ST_AsGeoJson(binary)Convert to GeoJSONExport data for web applications

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GeoJSON Examples

Point Geometry: 
-- Convert GeoJSON to geometry
SELECT ST_AsText(ST_GeomFromGeoJson('{"type":"Point","coordinates":[-122.4194,37.7749]}'))
-- Returns: POINT (-122.4194 37.7749)

-- Convert WKT to GeoJSON  
SELECT ST_AsGeoJson(ST_GeomFromText('POINT (-122.4194 37.7749)'))
-- Returns: {"type":"Point","coordinates":[-122.4194,37.7749],"crs":{"type":"name","properties":{"name":"EPSG:0"}}}
Point Geography: 
-- Create geography from GeoJSON
SELECT ST_AsGeoJson(ST_GeogFromGeoJson('{"type":"Point","coordinates":[-122.4194,37.7749]}'))
-- Returns: {"type":"Point","coordinates":[-122.4194,37.7749],"crs":{"type":"name","properties":{"name":"EPSG:4326"}}}
Complex Geometries: 
-- MultiLineString example
SELECT ST_AsGeoJson(ST_GeomFromText('MULTILINESTRING ((1 1, 5 1), (2 4, 4 4))'))
-- Returns:
{
  "type":"MultiLineString",
  "coordinates":[[[1,1],[5,1]],[[2,4],[4,4]]],
  "crs":{"type":"name","properties":{"name":"EPSG:0"}}
}

-- Convert back from GeoJSON
SELECT ST_AsText(ST_GeomFromGeoJson('{"type":"MultiLineString","coordinates":[[[1,1],[5,1]],[[2,4],[4,4]]]}'))
-- Returns: MULTILINESTRING ((1 1, 5 1), (2 4, 4 4))
Feature Collections: 
-- Working with GeoJSON Features
SELECT ST_GeomFromGeoJson('{
  "type": "Feature",
  "geometry": {
    "type": "Point", 
    "coordinates": [-122.4194, 37.7749]
  },
  "properties": {
    "name": "San Francisco",
    "population": 875000
  }
}')

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Data Type Conversion

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Between Geometry and Geography

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

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

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Format Conversions

-- WKT ↔ WKB
SELECT ST_AsText(ST_GeomFromWKB(wkb_data))        -- WKB to WKT
SELECT ST_AsBinary(ST_GeomFromText(wkt_string))   -- WKT to WKB

-- WKT ↔ GeoJSON  
SELECT ST_AsGeoJson(ST_GeomFromText(wkt_string))  -- WKT to GeoJSON
SELECT ST_AsText(ST_GeomFromGeoJson(geojson))     -- GeoJSON to WKT

-- WKB ↔ GeoJSON
SELECT ST_AsGeoJson(ST_GeomFromWKB(wkb_data))     -- WKB to GeoJSON  
SELECT ST_AsBinary(ST_GeomFromGeoJson(geojson))   -- GeoJSON to WKB

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Schema Configuration

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Basic Geospatial Column

{
  "schemaName": "spatial_data",
  "dimensionFieldSpecs": [
    {
      "name": "location",
      "dataType": "BYTES",
      "transformFunction": "toSphericalGeography(stPoint(longitude, latitude))"
    }
  ]
}

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Multiple Format Support

{
  "schemaName": "multi_format_spatial",
  "dimensionFieldSpecs": [
    {
      "name": "point_from_coords", 
      "dataType": "BYTES",
      "transformFunction": "toSphericalGeography(stPoint(lon, lat))"
    },
    {
      "name": "geom_from_wkt",
      "dataType": "BYTES", 
      "transformFunction": "ST_GeomFromText(wkt_column)"
    },
    {
      "name": "geog_from_geojson",
      "dataType": "BYTES",
      "transformFunction": "ST_GeogFromGeoJson(geojson_column)"
    }
  ]
}

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Best Practices

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Coordinate Order

Important: Always use longitude, latitude order (X, Y) in functions, which matches GeoJSON standard but differs from some other systems that use latitude, longitude.
-- Correct: longitude first, latitude second
ST_Point(-122.4194, 37.7749)  -- San Francisco

-- Incorrect: would place point in Antarctica  
ST_Point(37.7749, -122.4194)

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Choosing the Right Type

-- For global applications, prefer geography
"transformFunction": "toSphericalGeography(stPoint(longitude, latitude))"

-- For regional analysis, geometry may be sufficient
"transformFunction": "stPoint(x_coordinate, y_coordinate)"

-- For existing GeoJSON data
"transformFunction": "ST_GeogFromGeoJson(geojson_field)"

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Performance Considerations

  • Geography calculations are ~10-20% slower than geometry but more accurate
  • GeoJSON parsing has slight overhead compared to WKT
  • WKB format is most compact for storage
  • Multiple formats in the same table are supported but increase storage