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WKB - Well-Known Binary

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Well-Known Binary (WKB) is a binary version of Well-known Text

Overview​

Well-known binary (WKB) representations are typically shown in hexadecimal strings.

Variations​

  • EKWB - Adds spatial reference systems
  • TWKB

Alternatives​

  • WKT
  • GeoJSON Geometry
  • GML Geometry
FormatSupportDescription
WKB❌
TWKB❌WKB variant reduces binary size ~2x.

TWKB uses varints, precision truncation and zigzag point encoding to reduce binary size ~2x (however compressed size reduction is less)

Version History​

TBA.

Ecosystem Support​

  • PostGIS offers a function to return geometries in TWKB format: ST_AsTWKB.

Format Details​

The first byte indicates the byte order for the data:

  • 00 : big endian
  • 01 : little endian

The next 4 bytes are a 32-bit unsigned integer for the geometry type, as described below:

| Type | Supported | 2D | Z | M | ZM | | -------------------- | --------- | ---- | ---- | ---- | | Geometry | ✅ | 0000 | 1000 | 2000 | 3000 | | Point | ✅ | 0001 | 1001 | 2001 | 3001 | | LineString | ✅ | 0002 | 1002 | 2002 | 3002 | | Polygon | ✅ | 0003 | 1003 | 2003 | 3003 | | MultiPoint | ✅ | 0004 | 1004 | 2004 | 3004 | | MultiLineString | ✅ | 0005 | 1005 | 2005 | 3005 | | MultiPolygon | ✅ | 0006 | 1006 | 2006 | 3006 | | GeometryCollection | ✅ * | 0007 | 1007 | 2007 | 3007 | | | | | | | | | CircularString | ❌ | 0008 | 1008 | 2008 | 3008 | | CompoundCurve | ❌ | 0009 | 1009 | 2009 | 3009 | | CurvePolygon | ❌ | 0010 | 1010 | 2010 | 3010 | | MultiCurve | ❌ | 0011 | 1011 | 2011 | 3011 | | MultiSurface | ❌ | 0012 | 1012 | 2012 | 3012 | | Curve | ❌ | 0013 | 1013 | 2013 | 3013 | | Surface | ❌ | 0014 | 1014 | 2014 | 3014 | | PolyhedralSurface | ❌ | 0015 | 1015 | 2015 | 3015 | | TIN | ❌ | 0016 | 1016 | 2016 | 3016 | | Triangle | ❌ | 0017 | 1017 | 2017 | 3017 | | Circle | ❌ | 0018 | 1018 | 2018 | 3018 | | GeodesicString | ❌ | 0019 | 1019 | 2019 | 3019 | | EllipticalCurve | ❌ | 0020 | 1020 | 2020 | 3020 | | NurbsCurve | ❌ | 0021 | 1021 | 2021 | 3021 | | Clothoid | ❌ | 0022 | 1022 | 2022 | 3022 | | SpiralCurve | ❌ | 0023 | 1023 | 2023 | 3023 | | CompoundSurface | ❌ | 0024 | 1024 | 2024 | 3024 | | BrepSolid | ❌ | | 1025 | | | | AffinePlacement | ❌ | 102 | 1102 | | |

Remarks:

  • Many implementations, including loaders.gl, only handle the core GeoJSON geometry equivalents (points, line strings, polygons and to a varying degrees geometry collections of the same).
  • GeometryCollection can be difficult for some clients to handle.