Well-Known Binary (WKB) Format

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 co-ordinates.

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 co-ordinate is 2.0
    • 000000000140000000000000004010000000000000
  • The Y-co-ordinate is 4.0
    • 000000000140000000000000004010000000000000

Comments

Comments loading...