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.

Parameters:

centerdict, Sequence[float], ExprRef, Vector2number

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

Default value: [0, 0]

clipAngledict, float, ExprRef

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

clipExtentdict, ExprRef, Vector2Vector2number, Sequence[Sequence[float], Vector2number]

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.

coefficientdict, float, ExprRef

The coefficient parameter for the hammer projection.

Default value: 2

distancedict, float, ExprRef

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

extentdict, ExprRef, Vector2Vector2number, Sequence[Sequence[float], Vector2number]

fitdict, Fit, ExprRef, GeoJsonFeature, GeoJsonFeatureCollection, Sequence[dict, GeoJsonFeature], Sequence[dict, Fit, GeoJsonFeature, GeoJsonFeatureCollection, Sequence[dict, GeoJsonFeature]]

fractiondict, float, ExprRef

The fraction parameter for the bottomley projection.

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

lobesdict, float, ExprRef

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

paralleldict, float, ExprRef

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.

parallelsdict, Sequence[float], ExprRef

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

pointRadiusdict, float, ExprRef

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

precisiondict, float, ExprRef

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….

radiusdict, float, ExprRef

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

ratiodict, float, ExprRef

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

reflectXbool, dict, ExprRef

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

reflectYbool, dict, ExprRef

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

rotatedict, Sequence[float], ExprRef, 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]

scaledict, float, ExprRef

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.

sizedict, Sequence[float], ExprRef, Vector2number

Used in conjunction with fit, provides the width and height in pixels of the area to which the projection should be automatically fit.

spacingdict, float, ExprRef

The spacing parameter for the lagrange projection.

Default value: 0.5

tiltdict, float, ExprRef

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

Default value: 0.

translatedict, Sequence[float], ExprRef, Vector2number

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

typedict, ExprRef, 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])	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.