Object Attributes

ObjectAttribute (Entity)

Base class holding elements information/meta-data defining object attributes. It does not hold the attribute data directly but simply points to the database to retrieve it dynamically so that the values are always up-to-date.

An attribute can be either static or dynamic, i-e its value will be recomputed according to the defined expression/condition each time. Therefore it is not valid to have a dynamic attribute without expression.

An ObjectAttribute requires a parent ObjectDB, it is therefore not advised to instantiate any descendant of this class directly. Object attribute creation should be done through the GeoRefObject instead.

Parameters:

Name	Type	Description	Default
db	ObjectDB	reference ObjectDB to get data from.	required
name	str	attribute name.	required
expr	str	[Optional] attribute is computed as a condition or expression of other attributes.	None
dynamic	bool	[Optional] attributes values are recomputed each time the data is requested. expr must be defined if attribute is dynamic.	False
read_only	bool	[Optional] attribute data is protected.	False

Exceptions:

Type	Description
ValueError	ObjectDB or name is not provided.
ValueError	Attribute is dynamic but expr is not provided.

Attributes:

Name	Type	Description
name	str	name of the attribute.
expr	str	expression or condition to compute the attribute data.
dynamic	bool	if True, data is recomputed by ObjectDB each time it is accessed.
read_only	bool	wheter the attribute is considered read-only.

dynamic: bool property readonly

Return whether the attribute is dynamic, i-e. its data is recomputed using the provided expression.

Returns:

Type	Description
bool	True if dynamic, False otherwise.

expr: str property readonly

Return the attribute expression if provided at creation, otherwise None.

Returns:

Type	Description
str	Attribute expression.

name: str property readonly

Return the attribute name.

Returns:

Type	Description
str	Attribute name.

read_only: bool property readonly

Return whether the attribute is read-only, i-e. its data is protected.

Returns:

Type	Description
bool	True if read-only, False otherwise.

data(self, region=None)

Return the data associated to this attribute. If dynamic, the data will be recomputed first according to its provided expression.

Returns:

Type	Description
np.ndarray	Underlying attribute data array.

ObjectProperty (ObjectAttribute)

Property attribute class. See ObjectAttribute for more information.

Parameters:

Name	Type	Description	Default
db	ObjectDB	reference ObjectDB to get data from.	required
name	str	property name.	required
kind	PropertyKind	[Optional] property kind, see PropertyKind enum for more available kind.	None
unit	Unit	[Optional] property unit, see Unit in pint for more information.	None
expr	str	[Optional] property is computed as an expression of other attributes.	None
dynamic	bool	[Optional] attributes values are recomputed each time the data is requested. expr must be defined if property is dynamic.	False
read_only	bool	[Optional] attribute data is protected.	False

Exceptions:

Type	Description
ValueError	ObjectDB or name is not provided.
ValueError	Property is dynamic but expr is not provided.

Attributes:

Name	Type	Description
kind	PropertyKind	property kind if defined, otherwise None.
unit	Unit	property unit if defined, otherwise None.

kind: PropertyKind property readonly

Return the kind associated to the property if any, None otherwise.

Returns:

Type	Description
PropertyKind	Property kind.

unit: Unit property readonly

Return the unit associated to the property if any, None otherwise.

Returns:

Type	Description
Unit	Pint Unit.

ObjectRegion (ObjectAttribute)

Region attribute class. See ObjectAttribute for more information.

Parameters:

Name	Type	Description	Default
db	ObjectDB	reference ObjectDB to get data from.	required
name	str	region name.	required
condition	str	[Optional] region is computed as a condition of other attributes.	None
dynamic	bool	[Optional] attributes values are recomputed each time the data is requested. expr must be defined if property is dynamic.	False
read_only	bool	[Optional] attribute data is protected.	False

Exceptions:

Type	Description
ValueError	ObjectDB or name is not provided.
ValueError	Region is dynamic but expr is not provided.