Polygon

class lsst.images.Polygon(*, x_vertices: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | complex | bytes | str | _NestedSequence[complex | bytes | str], y_vertices: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | complex | bytes | str | _NestedSequence[complex | bytes | str])

Bases: Region

A simple 2-d polygon in Euclidean coordinates, with no holes.

Parameters

x_vertices

The x coordinates of the vertices of the polygon.

y_vertices

The y coordinate of the vertices of the polygon.

Attributes Summary

area	The area of the region (float).
bbox	The integer-coordinate bounding box of the region (Box).
n_vertices	The number of vertices in the polygon.
wkt	The 'Well-Known Text' representation of this region (str).
x_vertices	The x coordinates of the vertices of the polygon.
y_vertices	The y coordinates of the vertices of the polygon.

Methods Summary

contains([other, x, y])	Test whether the geometry contains the given points or another geometry.
difference(other)	Compute the point-set difference of this region with another.
from_box(box)	Construct from an integer-coordinate box.
from_legacy(legacy)	Convert from a legacy lsst.afw.geom.Polygon instance.
from_wkt(wkt)	Construct from a 'Well-Known Text' string.
intersection(other)	Compute the intersection of this region with a Bounds object.
serialize()	Serialize the region to a Pydantic model.
to_legacy()	Convert to a legacy lsst.afw.geom.Polygon instance.
to_shapely()	Convert to a shapely.Polygon or shapely.MultiPolygon object.
try_to_box()	If the underlying geometry is a rectangle that fully covers integer pixels (i.e. has all vertices at half-integer positions), return the equivalent Box.
try_to_polygon()	If the underlying geometry is a single polygon with no holes, return a Polygon instance holding it.
union(other)	Compute the point-set union of this region with another.

Attributes Documentation

area

The area of the region (float).

bbox

The integer-coordinate bounding box of the region (Box).

Because a Box logically contains the entirety of the pixels on its boundary, but the centers of those pixels are the numerical values of its bounds, the region may contain vertices that are up to 0.5 beyond the integer box coordinates in either dimension.

n_vertices

The number of vertices in the polygon.

wkt

The ‘Well-Known Text’ representation of this region (str).

x_vertices

The x coordinates of the vertices of the polygon.

This is a read-only array; polygons are immutable.

y_vertices

The y coordinates of the vertices of the polygon.

This is a read-only array; polygons are immutable.

Methods Documentation

contains(other: Region | None = None, *, x: float | int | ndarray | None = None, y: float | int | ndarray | None = None) → bool | ndarray

Test whether the geometry contains the given points or another geometry.

Parameters

other

Another geometry to compare to. Not compatible with the y and x arguments.

x

One or more floating-point or integer X coordinates to test for containment. If an array, an array of results will be returned.

y

One or more floating-point or integer Y coordinates to test for containment. If an array, an array of results will be returned.

difference(other: Region) → Region

Compute the point-set difference of this region with another.

static from_box(box: Box) → Polygon

Construct from an integer-coordinate box.

Notes

Because the integer min and max coordinates of the box are interpreted as pixel centers, these are expanded by 0.5 on all sides before using them to form the polygon vertices.

static from_legacy(legacy: LegacyPolygon) → Polygon

Convert from a legacy lsst.afw.geom.Polygon instance.

static from_wkt(wkt: str) → Region

Construct from a ‘Well-Known Text’ string.

intersection(other: Bounds) → Bounds

Compute the intersection of this region with a Bounds object.

Notes

Because Region implements the Bounds interface, its intersections need to support all other Bounds objects. This is not true of other Region point-set operations like union and difference.

serialize() → RegionSerializationModel

Serialize the region to a Pydantic model.

Region serialization uses a subset of the GeoJSON specification (IETF RFC 7946).

to_legacy() → LegacyPolygon

Convert to a legacy lsst.afw.geom.Polygon instance.

to_shapely() → Polygon | MultiPolygon

Convert to a shapely.Polygon or shapely.MultiPolygon object.

try_to_box() → Region | Box

If the underlying geometry is a rectangle that fully covers integer pixels (i.e. has all vertices at half-integer positions), return the equivalent Box.

In all other cases self is returned.

try_to_polygon() → Region

If the underlying geometry is a single polygon with no holes, return a Polygon instance holding it.

In all other cases self is returned.

union(other: Region) → Region

Compute the point-set union of this region with another.