NewSpatialFunction returns a new `SpatialFunction` instance configured by 'uri'.

RegisterSpatialFunction registers 'scheme' as a key pointing to 'init_func' in an internal lookup table used to create new `SpatialFunction` instances by the `NewSpatialFunction` method.

SpatialFunctionSchemes returns the list of schemes that have been registered.

SpatialFunction in an interface for spatial functions.

SpatialFunctionInitializationFunc is a function defined by individual function package and used to create an instance of that function.