class astropy.visualization.wcsaxes.Quadrangle(anchor, width, height, resolution=100, vertex_unit=Unit('deg'), **kwargs)[source]

Bases: matplotlib.patches.Polygon

Create a patch representing a latitude-longitude quadrangle.

The edges of the quadrangle lie on two lines of constant longitude and two lines of constant latitude (or the equivalent component names in the coordinate frame of interest, such as right ascension and declination). Note that lines of constant latitude are not great circles.

Unlike matplotlib.patches.Rectangle, the edges of this patch will render as curved lines if appropriate for the WCS transformation.

anchortuple or Quantity

This can be either a tuple of two Quantity objects, or a single Quantity array with two elements.


The width of the quadrangle in longitude (or, e.g., right ascension)


The height of the quadrangle in latitude (or, e.g., declination)

resolutionint, optional

The number of points that make up each side of the quadrangle - increase this to get a smoother quadrangle.


The units in which the resulting polygon should be defined - this should match the unit that the transformation (e.g. the WCS transformation) expects as input.


Additional keyword arguments are passed to Polygon

xy is a numpy array with shape Nx2.

If closed is True, the polygon will be closed so the starting and ending points are the same.

Valid keyword arguments are:


agg_filter: a filter function, which takes a (m, n, 3) float array and a dpi value, and returns a (m, n, 3) array alpha: float or None animated: bool antialiased or aa: unknown capstyle: {‘butt’, ‘round’, ‘projecting’} clip_box: Bbox clip_on: bool clip_path: Patch or (Path, Transform) or None color: color contains: unknown edgecolor or ec: color or None or ‘auto’ facecolor or fc: color or None figure: Figure fill: bool gid: str hatch: {‘/’, ‘\’, ‘|’, ‘-‘, ‘+’, ‘x’, ‘o’, ‘O’, ‘.’, ‘*’} in_layout: bool joinstyle: {‘miter’, ‘round’, ‘bevel’} label: object linestyle or ls: {‘-‘, ‘–’, ‘-.’, ‘:’, ‘’, (offset, on-off-seq), …} linewidth or lw: float or None path_effects: AbstractPathEffect picker: None or bool or callable rasterized: bool or None sketch_params: (scale: float, length: float, randomness: float) snap: bool or None transform: Transform url: str visible: bool zorder: float