Elements

class geoalchemy2.elements._SpatialElement(data, srid: int = -1, extended: bool | None = None)

Bases: object

The base class for public spatial elements.

Parameters:

• data – The first argument passed to the constructor is the data wrapped by the _SpatialElement object being constructed.

• srid – An integer representing the spatial reference system. E.g. 4326. Default value is -1, which means no/unknown reference system.

• extended – A boolean indicating whether the extended format (EWKT or EWKB) is used. Default is None.

data

extended

srid

class geoalchemy2.elements.WKTElement(data: str, srid: int = -1, extended: bool | None = None)

Bases: _SpatialElement

Instances of this class wrap a WKT or EWKT value.

Usage examples:

wkt_element_1 = WKTElement('POINT(5 45)')
wkt_element_2 = WKTElement('POINT(5 45)', srid=4326)
wkt_element_3 = WKTElement('SRID=4326;POINT(5 45)', extended=True)

Note::

This class uses __slots__ to restrict its attributes and improve memory efficiency by preventing the creation of a dynamic __dict__ for each instance. If you require dynamic attributes or support for weak references, use the DynamicWKTElement subclass, which provides these capabilities.

SPLIT_WKT_PATTERN = re.compile('((SRID=\\d+) *; *)?([\\w ]+) *(\\([-\\d\\. ,\\(\\)eE]+\\))')

as_ewkt() → WKTElement

as_wkt() → WKTElement

property desc: str

This element’s description string.

geom_from: str = 'ST_GeomFromText'

geom_from_extended_version: str = 'ST_GeomFromEWKT'

class geoalchemy2.elements.WKBElement(data: str | bytes | memoryview, srid: int = -1, extended: bool | None = None)

Bases: _SpatialElement

Instances of this class wrap a WKB or EWKB value.

Geometry values read from the database are converted to instances of this type. In most cases you won’t need to create WKBElement instances yourself.

If extended is True and srid is -1 at construction time then the SRID will be read from the EWKB data.

Note: you can create WKBElement objects from Shapely geometries using the geoalchemy2.shape.from_shape() function.

Note::

This class uses __slots__ to restrict its attributes and improve memory efficiency by preventing the creation of a dynamic __dict__ for each instance. If you require dynamic attributes or support for weak references, use the DynamicWKBElement subclass, which provides these capabilities.

as_ewkb() → WKBElement

as_wkb() → WKBElement

property desc: str

This element’s description string.

geom_from: str = 'ST_GeomFromWKB'

geom_from_extended_version: str = 'ST_GeomFromEWKB'

class geoalchemy2.elements.RasterElement(data: str | bytes | memoryview)

Bases: _SpatialElement

Instances of this class wrap a raster value.

Raster values read from the database are converted to instances of this type. In most cases you won’t need to create RasterElement instances yourself.

Note::

This class uses __slots__ to restrict its attributes and improve memory efficiency by preventing the creation of a dynamic __dict__ for each instance. If you require dynamic attributes or support for weak references, use the DynamicRasterElement subclass, which provides these capabilities.

property desc: str

This element’s description string.

class geoalchemy2.elements.CompositeElement(base, field, type_)

Bases: FunctionElement

Instances of this class wrap a Postgres composite type.