The Well-Known Binary (WKB) representation for geometric values
is defined by the OpenGIS specification. It is also defined in
the ISO *SQL/MM Part 3: Spatial* standard.

WKB is used to exchange geometry data as binary streams
represented by `BLOB`

values
containing geometric WKB information.

WKB uses one-byte unsigned integers, four-byte unsigned integers, and eight-byte double-precision numbers (IEEE 754 format). A byte is eight bits.

For example, a WKB value that corresponds to ```
POINT(1
1)
```

consists of this sequence of 21 bytes (each
represented here by two hex digits):

0101000000000000000000F03F000000000000F03F

The sequence may be broken down into these components:

Byte order : 01 WKB type : 01000000 X : 000000000000F03F Y : 000000000000F03F

Component representation is as follows:

The byte order may be either 1 or 0 to indicate little-endian or big-endian storage. The little-endian and big-endian byte orders are also known as Network Data Representation (NDR) and External Data Representation (XDR), respectively.

The WKB type is a code that indicates the geometry type. Values from 1 through 7 indicate

`Point`

,`LineString`

,`Polygon`

,`MultiPoint`

,`MultiLineString`

,`MultiPolygon`

, and`GeometryCollection`

.A

`Point`

value has X and Y coordinates, each represented as a double-precision value.

WKB values for more complex geometry values are represented by more complex data structures, as detailed in the OpenGIS specification.