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:

centerExprRef, Dict[required=[expr]], Vector2number, Sequence[float]

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

Default value: [0, 0]

clipAngleExprRef, 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.

clipExtentExprRef, 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]], 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.

coefficientExprRef, Dict[required=[expr]], float

The coefficient parameter for the hammer projection.

Default value: 2

distanceExprRef, 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 given distance is acos(1 / distance) converted to degrees. If tilt is also applied, then more conservative clipping may be necessary.

Default value: 2.0

extentExprRef, Dict[required=[expr]], Vector2Vector2number, Sequence[Vector2number, Sequence[float]]

fitExprRef, 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]]]]

fractionExprRef, Dict[required=[expr]], float

The fraction parameter for the bottomley projection.

Default value: 0.5, corresponding to a sin(ψ) where ψ = π/6.

lobesExprRef, Dict[required=[expr]], float

The number of lobes in projections that support multi-lobe views: berghaus, gingery, or healpix. The default value varies based on the projection type.

parallelExprRef, Dict[required=[expr]], float

The parallel parameter for projections that support it: armadillo, bonne, craig, cylindricalEqualArea, cylindricalStereographic, hammerRetroazimuthal, loximuthal, or rectangularPolyconic. The default value varies based on the projection type.

parallelsExprRef, 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.

pointRadiusExprRef, Dict[required=[expr]], 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

precisionExprRef, 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….

radiusExprRef, Dict[required=[expr]], float

The radius parameter for the airy or gingery projection. The default value varies based on the projection type.

ratioExprRef, Dict[required=[expr]], float

The ratio parameter for the hill, hufnagel, or wagner projections. The default value varies based on the projection type.

reflectXExprRef, Dict[required=[expr]], bool

Sets whether or not the x-dimension is reflected (negated) in the output.

reflectYExprRef, Dict[required=[expr]], bool

Sets whether or not the y-dimension is reflected (negated) in the output.

rotateExprRef, 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]

scaleExprRef, 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.

sizeExprRef, 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.

spacingExprRef, Dict[required=[expr]], float

The spacing parameter for the lagrange projection.

Default value: 0.5

tiltExprRef, Dict[required=[expr]], float

The tilt angle (in degrees) for the satellite projection.

Default value: 0.

translateExprRef, Dict[required=[expr]], Vector2number, Sequence[float]

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

typeExprRef, 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

__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