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
Projection
, Dict- Parameters:
- center
ExprRef
, Dict[required=[expr]],Vector2number
, Sequence[float] The projection’s center, a two-element array of longitude and latitude in degrees.
Default value:
[0, 0]
- clipAngle
ExprRef
, Dict[required=[expr]], 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
ExprRef
, Dict[required=[expr]],Vector2Vector2number
, Sequence[Vector2number
, Sequence[float]] 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
ExprRef
, Dict[required=[expr]], float The coefficient parameter for the
hammer
projection.Default value:
2
- distance
ExprRef
, Dict[required=[expr]], float For the
satellite
projection, the distance from the center of the sphere to the point of view, as a proportion of the sphere’s radius. The recommended maximum clip angle for a givendistance
is acos(1 / distance) converted to degrees. If tilt is also applied, then more conservative clipping may be necessary.Default value:
2.0
- extent
ExprRef
, Dict[required=[expr]],Vector2Vector2number
, Sequence[Vector2number
, Sequence[float]] - fit
ExprRef
, Dict[required=[expr]],Fit
,GeoJsonFeatureCollection
, Dict[required=[features, type]],GeoJsonFeature
, Dict[required=[geometry, properties, type]], Sequence[GeoJsonFeature
, Dict[required=[geometry, properties, type]]], Sequence[Fit
,GeoJsonFeatureCollection
, Dict[required=[features, type]],GeoJsonFeature
, Dict[required=[geometry, properties, type]], Sequence[GeoJsonFeature
, Dict[required=[geometry, properties, type]]]] - fraction
ExprRef
, Dict[required=[expr]], float The fraction parameter for the
bottomley
projection.Default value:
0.5
, corresponding to a sin(ψ) where ψ = π/6.- lobes
ExprRef
, Dict[required=[expr]], float The number of lobes in projections that support multi-lobe views:
berghaus
,gingery
, orhealpix
. The default value varies based on the projection type.- parallel
ExprRef
, Dict[required=[expr]], float The parallel parameter for projections that support it:
armadillo
,bonne
,craig
,cylindricalEqualArea
,cylindricalStereographic
,hammerRetroazimuthal
,loximuthal
, orrectangularPolyconic
. The default value varies based on the projection type.- parallels
ExprRef
, Dict[required=[expr]], Sequence[float] For conic projections, the two standard parallels that define the map layout. The default depends on the specific conic projection used.
- pointRadius
ExprRef
, Dict[required=[expr]], 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
ExprRef
, Dict[required=[expr]], 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
ExprRef
, Dict[required=[expr]], float The radius parameter for the
airy
orgingery
projection. The default value varies based on the projection type.- ratio
ExprRef
, Dict[required=[expr]], float The ratio parameter for the
hill
,hufnagel
, orwagner
projections. The default value varies based on the projection type.- reflectX
ExprRef
, Dict[required=[expr]], bool Sets whether or not the x-dimension is reflected (negated) in the output.
- reflectY
ExprRef
, Dict[required=[expr]], bool Sets whether or not the y-dimension is reflected (negated) in the output.
- rotate
ExprRef
, Dict[required=[expr]],Vector2number
, Sequence[float],Vector3number
, Sequence[float] 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
ExprRef
, Dict[required=[expr]], 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
ExprRef
, Dict[required=[expr]],Vector2number
, Sequence[float] Used in conjunction with fit, provides the width and height in pixels of the area to which the projection should be automatically fit.
- spacing
ExprRef
, Dict[required=[expr]], float The spacing parameter for the
lagrange
projection.Default value:
0.5
- tilt
ExprRef
, Dict[required=[expr]], float The tilt angle (in degrees) for the
satellite
projection.Default value:
0
.- translate
ExprRef
, Dict[required=[expr]],Vector2number
, Sequence[float] The projection’s translation offset as a two-element array
[tx, ty]
.- type
ExprRef
, Dict[required=[expr]],ProjectionType
, Literal[‘albers’, ‘albersUsa’, ‘azimuthalEqualArea’, ‘azimuthalEquidistant’, ‘conicConformal’, ‘conicEqualArea’, ‘conicEquidistant’, ‘equalEarth’, ‘equirectangular’, ‘gnomonic’, ‘identity’, ‘mercator’, ‘naturalEarth1’, ‘orthographic’, ‘stereographic’, ‘transverseMercator’] 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:
equalEarth
- center
- __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, indent, sort_keys, ...])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 rootschema