geometryExtended constant

BinaryFormat<GeometryContent> const geometryExtended

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);