Region

class lsst.images.Region(geometry: Polygon | MultiPolygon)

Bases: object

A 2-d Euclidean region represented as one or more polygons with optional holes.

Parameters

geometry

A polygon or multi-polygon from the Shapely library.

Attributes Summary

area	The area of the region (float).
bbox	The integer-coordinate bounding box of the region (Box).
wkt	The 'Well-Known Text' representation of this region (str).

Methods Summary

contains()	Test whether the geometry contains the given points or another geometry.
difference(other)	Compute the point-set difference of this region with another.
from_wkt(wkt)	Construct from a 'Well-Known Text' string.
intersection()	Compute the intersection of this region with a Bounds object.
serialize()	Serialize the region to a Pydantic model.
to_shapely()	Convert to a shapely.Polygon or shapely.MultiPolygon object.
transform(transform)	Transform the coordinates of the region, returning a new one.
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.

wkt

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

Methods Documentation

contains(point: XY[int | float] | YX[int | float], /) → bool

contains(point: XY[Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | complex | bytes | str | _NestedSequence[complex | bytes | str]] | YX[Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | complex | bytes | str | _NestedSequence[complex | bytes | str]], /) → ndarray

contains(*, x: int | float, y: int | float) → bool

contains(*, x: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | complex | bytes | str | _NestedSequence[complex | bytes | str], y: Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | complex | bytes | str | _NestedSequence[complex | bytes | str]) → ndarray

contains(other: Polygon, /) → bool

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

Parameters

other

Another geometry, or an XY or YX coordinate pair, to compare to. Mutually exclusive with x and y.

x

One or more X coordinates to test for containment, as a scalar or any array-like. Results are broadcast against y. Mutually exclusive with other.

y

One or more Y coordinates to test for containment, as a scalar or any array-like. Results are broadcast against x. Mutually exclusive with other.

difference(other: Region) → Region

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

Parameters

other

Region to subtract from this one.

static from_wkt(wkt: str) → Region

Construct from a ‘Well-Known Text’ string.

Parameters

wkt

Well-Known Text representation of the region.

intersection(other: Region) → Region

intersection(other: Box) → Region | Box

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.

Parameters

other

Bounds to intersect with this region.

serialize() → RegionSerializationModel

Serialize the region to a Pydantic model.

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

to_shapely() → Polygon | MultiPolygon

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

transform(transform: Transform[Any, Any]) → Region

Transform the coordinates of the region, returning a new one.

Parameters

transform

Coordinate transform to apply (in the forward direction).

Notes

This applies the transform to all vertices, assuming that the transform is close enough to affine that the topology of the geometry does not change and straight-line edges do not need to be subsampled.

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.

Parameters

other

Region to union with this one.