Subgroup: other

# Class: QgsCircle¶

class `qgis.core.``QgsCircle`

Bases: `qgis._core.QgsEllipse`

QgsCircle(center: QgsPoint, radius: float, azimuth: float = 0) Constructs a circle by defining all the members.

Parameters: center – The center of the circle. radius – The radius of the circle. azimuth – Angle in degrees started from the North to the first quadrant.

QgsCircle(QgsCircle)

Circle geometry type.

A circle is defined by a center point with a radius and an azimuth. The azimuth is the north angle to the semi-major axis, in degrees. By default, the semi-major axis is oriented to the north (0 degrees).

New in version 3.0: Methods

 `area` `boundingBox` `contains` Returns true if the circle contains the `point`. `from2Points` Constructs a circle by 2 points on the circle. `from3Points` Constructs a circle by 3 points on the circle. `from3Tangents` Constructs a circle by 3 tangents on the circle (aka inscribed circle of a triangle). `fromCenterDiameter` Constructs a circle by a center point and a diameter. `fromCenterPoint` Constructs a circle by a center point and another point. `fromExtent` Constructs a circle by an extent (aka bounding box / `QgsRectangle`). `intersections` Calculates the intersections points between this circle and an `other` circle. `minimalCircleFrom3Points` Constructs the smallest circle from 3 points. `northQuadrant` The four quadrants of the ellipse. `outerTangents` Calculates the outer tangent points between this circle and an `other` circle. `perimeter` `radius` Returns the radius of the circle `setRadius` Sets the radius of the circle `setSemiMajorAxis` Inherited method. `setSemiMinorAxis` Inherited method. `tangentToPoint` Calculates the tangent points between this circle and the point `p`. `toCircularString` Returns a circular string from the circle. `toString`

Signals

Attributes

`area`(self) → float
`boundingBox`(self) → QgsRectangle
`contains`(self, point: QgsPoint, epsilon: float = 1e-08) → bool

Returns true if the circle contains the `point`.

`from2Points`(pt1: QgsPoint, pt2: QgsPoint) → QgsCircle

Constructs a circle by 2 points on the circle. The center point can have m value which is the result from the midpoint operation between `pt1` and `pt2`. Z dimension is also supported and is retrieved from the first 3D point amongst `pt1` and `pt2`. The radius is calculated from the 2D distance between `pt1` and `pt2`. The azimuth is the angle between `pt1` and `pt2`.

Parameters: pt1 – First point. pt2 – Second point.
`from3Points`(pt1: QgsPoint, pt2: QgsPoint, pt3: QgsPoint, epsilon: float = 1e-08) → QgsCircle

Constructs a circle by 3 points on the circle. M value is dropped for the center point. Z dimension is supported and is retrieved from the first 3D point amongst `pt1`, `pt2` and `pt3`. The azimuth always takes the default value. If the points are colinear an empty circle is returned.

Parameters: pt1 – First point. pt2 – Second point. pt3 – Third point. epsilon – Value used to compare point.
`from3Tangents`(pt1_tg1: QgsPoint, pt2_tg1: QgsPoint, pt1_tg2: QgsPoint, pt2_tg2: QgsPoint, pt1_tg3: QgsPoint, pt2_tg3: QgsPoint, epsilon: float = 1e-08) → QgsCircle

Constructs a circle by 3 tangents on the circle (aka inscribed circle of a triangle). Z and m values are dropped for the center point. The azimuth always takes the default value.

Parameters: pt1_tg1 – First point of the first tangent. pt2_tg1 – Second point of the first tangent. pt1_tg2 – First point of the second tangent. pt2_tg2 – Second point of the second tangent. pt1_tg3 – First point of the third tangent. pt2_tg3 – Second point of the third tangent. epsilon – Value used to compare point.
`fromCenterDiameter`(center: QgsPoint, diameter: float, azimuth: float = 0) → QgsCircle

Constructs a circle by a center point and a diameter. The center point keeps z and m values from `center`.

Parameters: center – Center point. diameter – Diameter of the circle. azimuth – Azimuth of the circle.
`fromCenterPoint`(center: QgsPoint, pt1: QgsPoint) → QgsCircle

Constructs a circle by a center point and another point. The center point keeps z and m values from `center`. Axes are calculated from the 2D distance between `center` and `pt1`. The azimuth is the angle between `center` and `pt1`.

Parameters: center – Center point. pt1 – A point on the circle.
`fromExtent`(pt1: QgsPoint, pt2: QgsPoint) → QgsCircle

Constructs a circle by an extent (aka bounding box / `QgsRectangle`). The center point can have m value which is the result from the midpoint operation between `pt1` and `pt2`. Z dimension is also supported and is retrieved from the first 3D point amongst `pt1` and `pt2`. Axes are calculated from the 2D distance between `pt1` and `pt2`. The azimuth always takes the default value.

Parameters: pt1 – First corner. pt2 – Second corner.
`intersections`(self, other: QgsCircle, useZ: bool = False) → Tuple[int, QgsPoint, QgsPoint]

Calculates the intersections points between this circle and an `other` circle.

If found, the intersection points will be stored in `intersection1` and `intersection2`.

By default this method does not consider any z values and instead treats the circles as 2-dimensional. If `useZ` is set to true, then an intersection will only occur if the z values of both circles are equal. In this case the points returned for `intersection1` and `intersection2` will contain the z value of the circle intersections.

Returns: number of intersection points found.

New in version 3.2.

`minimalCircleFrom3Points`(pt1: QgsPoint, pt2: QgsPoint, pt3: QgsPoint, epsilon: float = 1e-08) → QgsCircle

Constructs the smallest circle from 3 points. Z and m values are dropped for the center point. The azimuth always takes the default value. If the points are colinear an empty circle is returned.

Parameters: pt1 – First point. pt2 – Second point. pt3 – Third point. epsilon – Value used to compare point.
`northQuadrant`(self) → List[QgsPoint]

The four quadrants of the ellipse. They are oriented and started from North.

Returns: quadrants defined by four points.

`quadrant()`

`outerTangents`(self, other: QgsCircle) → Tuple[int, QgsPointXY, QgsPointXY, QgsPointXY, QgsPointXY]

Calculates the outer tangent points between this circle and an `other` circle.

The outer tangent points correspond to the points at which the two lines which are drawn so that they are tangential to both circles touch the circles.

The first tangent line is described by the points stored in `line1P1` and `line1P2`, and the second line is described by the points stored in `line2P1` and `line2P2`.

Returns the number of tangents (either 0 or 2).

Note that this method is 2D only and does not consider the z-value of the circle.

New in version 3.2.

`perimeter`(self) → float
`radius`(self) → float

Returns the radius of the circle

`setRadius`(self, radius: float)

Sets the radius of the circle

`setSemiMajorAxis`(self, semiMajorAxis: float)

`setSemiMinorAxis`(self, semiMinorAxis: float)

`tangentToPoint`(self, p: QgsPointXY) → Tuple[bool, QgsPointXY, QgsPointXY]

Calculates the tangent points between this circle and the point `p`.

If found, the tangent points will be stored in `pt1` and `pt2`.

Note that this method is 2D only and does not consider the z-value of the circle.

Returns: true if tangent was found.

New in version 3.2.

`toCircularString`(self, oriented: bool = False) → QgsCircularString

Returns a circular string from the circle.

Parameters: oriented – If oriented is true the start point is from azimuth instead from north.
`toString`(self, pointPrecision: int = 17, radiusPrecision: int = 17, azimuthPrecision: int = 2) → str