Well-Known Binary (WKB) Format

Understand the standard binary format for geometry. This overview explains how WKB represents spatial data types for storage and exchange.

WKB stands for Well-Known Binary, a format for representing geographical and geometrical data.

WKB uses 1-byte unsigned integers, 4-byte unsigned integers, and 8-byte double-precision numbers.

• The first byte indicates the byte order. 00 for big endian, or 01 for little endian.

• The next 4 bytes indicate the geometry type. Values from 1 to 7 indicate whether the type is Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, or GeometryCollection respectively.

• The 8-byte floats represent the coordinates.

Take the following example, a sequence of 21 bytes each represented by two hex digits:

000000000140000000000000004010000000000000

• It's big endian

  • 000000000140000000000000004010000000000000

• It's a POINT

  • 000000000140000000000000004010000000000000

• The X coordinate is 2.0

  • 000000000140000000000000004010000000000000

• The Y-coordinate is 4.0

  • 000000000140000000000000004010000000000000

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