altair.Projection

class altair.Projection(center=Undefined, clipAngle=Undefined, clipExtent=Undefined, coefficient=Undefined, distance=Undefined, extent=Undefined, fit=Undefined, fraction=Undefined, lobes=Undefined, parallel=Undefined, parallels=Undefined, pointRadius=Undefined, precision=Undefined, radius=Undefined, ratio=Undefined, reflectX=Undefined, reflectY=Undefined, rotate=Undefined, scale=Undefined, size=Undefined, spacing=Undefined, tilt=Undefined, translate=Undefined, type=Undefined, **kwds)

Projection schema wrapper

Mapping(required=[])

Attributes:

center : Vector2number

The projection’s center, a two-element array of longitude and latitude in degrees.

Default value: [0, 0]

clipAngle : float

The projection’s clipping circle radius to the specified angle in degrees. If null, switches to antimeridian cutting rather than small-circle clipping.

clipExtent : Vector2Vector2number

The projection’s viewport clip extent to the specified bounds in pixels. The extent bounds are specified as an array [[x0, y0], [x1, y1]], where x0 is the left-side of the viewport, y0 is the top, x1 is the right and y1 is the bottom. If null, no viewport clipping is performed.

coefficient : float

distance : float

extent : Vector2Vector2number

fit : anyOf(Fit, List(Fit))

fraction : float

lobes : float

parallel : float

parallels : List(float)

For conic projections, the two standard parallels that define the map layout. The default depends on the specific conic projection used.

pointRadius : float

The default radius (in pixels) to use when drawing GeoJSON Point and MultiPoint geometries. This parameter sets a constant default value. To modify the point radius in response to data, see the corresponding parameter of the GeoPath and GeoShape transforms.

Default value: 4.5

precision : float

The threshold for the projection’s adaptive resampling to the specified value in pixels. This value corresponds to the Douglas–Peucker distance. If precision is not specified, returns the projection’s current resampling precision which defaults to √0.5 ≅ 0.70710….

radius : float

ratio : float

reflectX : boolean

reflectY : boolean

rotate : anyOf(Vector2number, Vector3number)

The projection’s three-axis rotation to the specified angles, which must be a two- or three-element array of numbers [ lambda, phi, gamma ] specifying the rotation angles in degrees about each spherical axis. (These correspond to yaw, pitch and roll.)

Default value: [0, 0, 0]

scale : float

The projection’s scale (zoom) factor, overriding automatic fitting. The default scale is projection-specific. The scale factor corresponds linearly to the distance between projected points; however, scale factor values are not equivalent across projections.

size : Vector2number

spacing : float

tilt : float

translate : Vector2number

The projection’s translation offset as a two-element array [tx, ty].

type : ProjectionType

The cartographic projection to use. This value is case-insensitive, for example "albers" and "Albers" indicate the same projection type. You can find all valid projection types in the documentation.

Default value: mercator

__init__(center=Undefined, clipAngle=Undefined, clipExtent=Undefined, coefficient=Undefined, distance=Undefined, extent=Undefined, fit=Undefined, fraction=Undefined, lobes=Undefined, parallel=Undefined, parallels=Undefined, pointRadius=Undefined, precision=Undefined, radius=Undefined, ratio=Undefined, reflectX=Undefined, reflectY=Undefined, rotate=Undefined, scale=Undefined, size=Undefined, spacing=Undefined, tilt=Undefined, translate=Undefined, type=Undefined, **kwds)

Methods

__init__([center, clipAngle, clipExtent, …])
copy([deep, ignore])	Return a copy of the object
from_dict(dct[, validate, _wrapper_classes])	Construct class from a dictionary representation
from_json(json_string[, validate])	Instantiate the object from a valid JSON string
resolve_references([schema])	Resolve references in the context of this object’s schema or root schema.
to_dict([validate, ignore, context])	Return a dictionary representation of the object
to_json([validate, ignore, context, indent, …])	Emit the JSON representation for this object as a string.
validate(instance[, schema])	Validate the instance against the class schema in the context of the rootschema.
validate_property(name, value[, schema])	Validate a property against property schema in the context of the

copy(deep=True, ignore=())

Return a copy of the object

Parameters:

deep : boolean or list, optional

If True (default) then return a deep copy of all dict, list, and SchemaBase objects within the object structure. If False, then only copy the top object. If a list or iterable, then only copy the listed attributes.

ignore : list, optional

A list of keys for which the contents should not be copied, but only stored by reference.

from_dict(dct, validate=True, _wrapper_classes=None)

Construct class from a dictionary representation

Parameters:

dct : dictionary

The dict from which to construct the class

validate : boolean

If True (default), then validate the input against the schema.

_wrapper_classes : list (optional)

The set of SchemaBase classes to use when constructing wrappers of the dict inputs. If not specified, the result of cls._default_wrapper_classes will be used.

Returns:

obj : Schema object

The wrapped schema

Raises:

jsonschema.ValidationError :

if validate=True and dct does not conform to the schema

from_json(json_string, validate=True, **kwargs)

Instantiate the object from a valid JSON string

Parameters:

json_string : string

The string containing a valid JSON chart specification.

validate : boolean

If True (default), then validate the input against the schema.

**kwargs :

Additional keyword arguments are passed to json.loads

Returns:

chart : Chart object

The altair Chart object built from the specification.

resolve_references(schema=None)

Resolve references in the context of this object’s schema or root schema.

to_dict(validate=True, ignore=None, context=None)

Return a dictionary representation of the object

Parameters:

validate : boolean or string

If True (default), then validate the output dictionary against the schema. If “deep” then recursively validate all objects in the spec. This takes much more time, but it results in friendlier tracebacks for large objects.

ignore : list

A list of keys to ignore. This will not passed to child to_dict function calls.

context : dict (optional)

A context dictionary that will be passed to all child to_dict function calls

Returns:

dct : dictionary

The dictionary representation of this object

Raises:

jsonschema.ValidationError :

if validate=True and the dict does not conform to the schema

to_json(validate=True, ignore=[], context={}, indent=2, sort_keys=True, **kwargs)

Emit the JSON representation for this object as a string.

Parameters:

validate : boolean or string

If True (default), then validate the output dictionary against the schema. If “deep” then recursively validate all objects in the spec. This takes much more time, but it results in friendlier tracebacks for large objects.

ignore : list

A list of keys to ignore. This will not passed to child to_dict function calls.

context : dict (optional)

A context dictionary that will be passed to all child to_dict function calls

indent : integer, default 2

the number of spaces of indentation to use

sort_keys : boolean, default True

if True, sort keys in the output

**kwargs

Additional keyword arguments are passed to json.dumps()

Returns:

spec : string

The JSON specification of the chart object.

validate(instance, schema=None)

Validate the instance against the class schema in the context of the rootschema.

validate_property(name, value, schema=None)

Validate a property against property schema in the context of the rootschema