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]]
, wherex0
is the left-side of the viewport,y0
is the top,x1
is the right andy1
is the bottom. Ifnull
, 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
andMultiPoint
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
- center :