geometryExtended constant
The Extended WKB (EWKB) format for geometries.
Use encoder
and encoder
methods of the format instance to access an
encoder or an decoder for EWKB.
Supported geometry types and their "WKB integer codes" for different coordinate types:
Geometry | 2D | Z | M | ZM |
---|---|---|---|---|
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 |
When encoding EWKB data 2D type codes are used with dimensionalty flags added as described below.
Supports also Extended WKB (EWKB) flags on a geometry type:
- 3D coordinates: flag
0x80000000
is set - Measured coordinates: flag
0x40000000
is set - CRS known:
0x20000000
is set
For WKB binary data encoding, the Endian.little
(NDR) byte order is used
by default, however when accessing an encoder it's possible to specify
also the Endian.big
(XDR) byte order.
See also geometry to get a format for the standard WKB.
Implementation
static const BinaryFormat<GeometryContent> geometryExtended =
_WkbGeometryBinaryFormat(flavor: WkbFlavor.extended);