Class: QgsCircle¶
- class qgis.core.QgsCircle¶
Bases:
QgsEllipse
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).
QgsCircle()
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
)Methods
- rtype:
float
Returns a GML2 representation of the geometry.
Returns a GML3 representation of the geometry.
- rtype:
QgsRectangle
Returns
True
if the circle contains thepoint
.Constructs a circle by 2 points on the circle.
Constructs a circle by 3 points on the circle.
Constructs a circle by 3 tangents on the circle (aka inscribed circle of a triangle).
Returns an array of circle constructed by 3 tangents on the circle (aka inscribed circle of a triangle).
Constructs a circle by a center point and a diameter.
Constructs a circle by a center point and another point.
Constructs a circle by an extent (aka bounding box /
QgsRectangle
).Calculates the inner tangent points between this circle and an
other
circle.Calculates the intersections points between this circle and an
other
circle.Constructs the smallest circle from 3 points.
The four quadrants of the ellipse.
Calculates the outer tangent points between this circle and an
other
circle.- rtype:
float
Returns the radius of the circle
Sets the radius of the circle
Inherited method.
Inherited method.
Calculates the tangent points between this circle and the point
p
.Returns a circular string from the circle.
- param pointPrecision:
- area(self) float ¶
- Return type:
float
- asGml2(self, doc: QDomDocument, precision: int = 17, ns: str = '', axisOrder: QgsAbstractGeometry.AxisOrder = QgsAbstractGeometry.AxisOrder.XY) QDomElement ¶
Returns a GML2 representation of the geometry. Since GML2 does not supports curve, it will be converted to a LineString.
- Parameters:
doc (QDomDocument) – DOM document
precision (int = 17) – number of decimal places for coordinates
ns (str = '') – XML namespace
axisOrder (QgsAbstractGeometry.AxisOrder = QgsAbstractGeometry.AxisOrder.XY) – Axis order for generated GML
See also
- Return type:
QDomElement
- asGml3(self, doc: QDomDocument, precision: int = 17, ns: str = '', axisOrder: QgsAbstractGeometry.AxisOrder = QgsAbstractGeometry.AxisOrder.XY) QDomElement ¶
Returns a GML3 representation of the geometry.
From the GML3 description: A Circle is an arc whose ends coincide to form a simple closed loop. The three control points shall be distinct non-co-linear points for the circle to be unambiguously defined. The arc is simply extended past the third control point until the first control point is encountered.
Coordinates are taken from quadrant North, East and South.
- Parameters:
doc (QDomDocument) – DOM document
precision (int = 17) – number of decimal places for coordinates
ns (str = '') – XML namespace
axisOrder (QgsAbstractGeometry.AxisOrder = QgsAbstractGeometry.AxisOrder.XY) – Axis order for generated GML
See also
- Return type:
QDomElement
- boundingBox(self) QgsRectangle ¶
- Return type:
- contains(self, point: QgsPoint, epsilon: float = 1e-08) bool ¶
Returns
True
if the circle contains thepoint
.- Parameters:
point (QgsPoint) –
epsilon (float = 1e-08) –
- Return type:
bool
- 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
andpt2
. Z dimension is also supported and is retrieved from the first 3D point amongstpt1
andpt2
. The radius is calculated from the 2D distance betweenpt1
andpt2
. The azimuth is the angle betweenpt1
andpt2
.
- 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
andpt3
. The azimuth always takes the default value. If the points are colinear an empty circle is returned.
- from3Tangents(pt1_tg1: QgsPoint, pt2_tg1: QgsPoint, pt1_tg2: QgsPoint, pt2_tg2: QgsPoint, pt1_tg3: QgsPoint, pt2_tg3: QgsPoint, epsilon: float = 1e-08, pos: QgsPoint = QgsPoint()) 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 (QgsPoint) – First point of the first tangent.
pt2_tg1 (QgsPoint) – Second point of the first tangent.
pt1_tg2 (QgsPoint) – First point of the second tangent.
pt2_tg2 (QgsPoint) – Second point of the second tangent.
pt1_tg3 (QgsPoint) – First point of the third tangent.
pt2_tg3 (QgsPoint) – Second point of the third tangent.
epsilon (float = 1e-08) – Value used to compare point.
pos (
QgsPoint
= QgsPoint()) – Point to determine which circle use in case of multi return. If the solution is not unique and pos is an empty point, an empty circle is returned. – This case happens only when two tangents are parallels. (since QGIS 3.18)
See also
Example¶
# [(0 0), (5 0)] and [(5 5), (10 5)] are parallels QgsCircle.from3Tangents(QgsPoint(0, 0), QgsPoint(5, 0), QgsPoint(5, 5), QgsPoint(10, 5), QgsPoint(2.5, 0), QgsPoint(7.5, 5)) # <QgsCircle: Empty> QgsCircle.from3Tangents(QgsPoint(0, 0), QgsPoint(5, 0), QgsPoint(5, 5), QgsPoint(10, 5), QgsPoint(2.5, 0), QgsPoint(7.5, 5), pos=QgsPoint(2, 0)) # <QgsCircle: Circle (Center: Point (1.46446609406726203 2.49999999999999911), Radius: 2.5, Azimuth: 0)> QgsCircle.from3Tangents(QgsPoint(0, 0), QgsPoint(5, 0), QgsPoint(5, 5), QgsPoint(10, 5), QgsPoint(2.5, 0), QgsPoint(7.5, 5), pos=QgsPoint(3, 0)) # <QgsCircle: Circle (Center: Point (8.53553390593273775 2.5), Radius: 2.5, Azimuth: 0)>
- rtype:
QgsCircle
- from3TangentsMulti(pt1_tg1: QgsPoint, pt2_tg1: QgsPoint, pt1_tg2: QgsPoint, pt2_tg2: QgsPoint, pt1_tg3: QgsPoint, pt2_tg3: QgsPoint, epsilon: float = 1e-08, pos: QgsPoint = QgsPoint()) List[QgsCircle] ¶
Returns an array of circle constructed by 3 tangents on the circle (aka inscribed circle of a triangle).
The vector can contain 0, 1 or 2 circles:
0: Impossible to construct a circle from 3 tangents (three parallel tangents)
1: The three tangents make a triangle or when two tangents are parallel there are two possible circles (see examples). If pos is not an empty point, we use its coordinates to determine which circle will be returned. More precisely the circle that will be returned will be the one whose center is on the same side as pos relative to the third tangent.
2: Returns both solutions when two tangents are parallel (this implies that pos is an empty point).
Z and m values are dropped for the center point. The azimuth always takes the default value.
- Parameters:
pt1_tg1 (QgsPoint) – First point of the first tangent.
pt2_tg1 (QgsPoint) – Second point of the first tangent.
pt1_tg2 (QgsPoint) – First point of the second tangent.
pt2_tg2 (QgsPoint) – Second point of the second tangent.
pt1_tg3 (QgsPoint) – First point of the third tangent.
pt2_tg3 (QgsPoint) – Second point of the third tangent.
epsilon (float = 1e-08) – Value used to compare point.
pos (
QgsPoint
= QgsPoint()) – (optional) Point to determine which circle use in case of multi return.
See also
Example¶
# [(0 0), (5 0)] and [(5 5), (10 5)] are parallels QgsCircle.from3TangentsMulti(QgsPoint(0, 0), QgsPoint(5, 0), QgsPoint(5, 5), QgsPoint(10, 5), QgsPoint(2.5, 0), QgsPoint(7.5, 5)) # [<QgsCircle: Circle (Center: Point (8.53553390593273775 2.5), Radius: 2.5, Azimuth: 0)>, <QgsCircle: Circle (Center: Point (1.46446609406726203 2.49999999999999911), Radius: 2.5, Azimuth: 0)>] QgsCircle.from3TangentsMulti(QgsPoint(0, 0), QgsPoint(5, 0), QgsPoint(5, 5), QgsPoint(10, 5), QgsPoint(2.5, 0), QgsPoint(7.5, 5), pos=QgsPoint(2, 0)) # [<QgsCircle: Circle (Center: Point (1.46446609406726203 2.49999999999999911), Radius: 2.5, Azimuth: 0)>] QgsCircle.from3TangentsMulti(QgsPoint(0, 0), QgsPoint(5, 0), QgsPoint(5, 5), QgsPoint(10, 5), QgsPoint(2.5, 0), QgsPoint(7.5, 5), pos=QgsPoint(3, 0)) # [<QgsCircle: Circle (Center: Point (8.53553390593273775 2.5), Radius: 2.5, Azimuth: 0)>] # [(0 0), (5 0)], [(5 5), (10 5)] and [(15 5), (20 5)] are parallels QgsCircle.from3TangentsMulti(QgsPoint(0, 0), QgsPoint(5, 0), QgsPoint(5, 5), QgsPoint(10, 5), QgsPoint(15, 5), QgsPoint(20, 5)) # []
- rtype:
List[QgsCircle]
- 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
.
- 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 betweencenter
andpt1
. The azimuth is the angle betweencenter
andpt1
.
- 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 betweenpt1
andpt2
. Z dimension is also supported and is retrieved from the first 3D point amongstpt1
andpt2
. Axes are calculated from the 2D distance betweenpt1
andpt2
. The azimuth always takes the default value.
- innerTangents(self, other: QgsCircle) Tuple[int, QgsPointXY, QgsPointXY, QgsPointXY, QgsPointXY] ¶
Calculates the inner tangent points between this circle and an
other
circle.The inner tangent points correspond to the points at which the two lines which are drawn so that they are tangential to both circles but on different sides, touching the circles and crossing each other.
The first tangent line is described by the points stored in
line1P1
andline1P2
, and the second line is described by the points stored inline2P1
andline2P2
.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.
See also
New in version 3.6.
- Parameters:
other (QgsCircle) –
- Return type:
Tuple[int,
QgsPointXY
,QgsPointXY
,QgsPointXY
, QgsPointXY]
- 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
andintersection2
.By default this method does not consider any z values and instead treats the circles as 2-dimensional. If
useZ
is set toTrue
, then an intersection will only occur if the z values of both circles are equal. In this case the points returned forintersection1
andintersection2
will contain the z value of the circle intersections.- Return type:
Tuple[int,
QgsPoint
, QgsPoint]- Returns:
number of intersection points found.
New in version 3.2.
- Parameters:
other (QgsCircle) –
useZ (bool = False) –
- 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.
- northQuadrant(self) List[QgsPoint] ¶
The four quadrants of the ellipse. They are oriented and started from North.
- Return type:
List[QgsPoint]
- Returns:
quadrants defined by four points.
See also
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
andline1P2
, and the second line is described by the points stored inline2P1
andline2P2
.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.
See also
New in version 3.2.
- Parameters:
other (QgsCircle) –
- Return type:
Tuple[int,
QgsPointXY
,QgsPointXY
,QgsPointXY
, QgsPointXY]
- perimeter(self) float ¶
- Return type:
float
- radius(self) float ¶
Returns the radius of the circle
- Return type:
float
- setRadius(self, radius: float)¶
Sets the radius of the circle
- Parameters:
radius (float) –
- setSemiMajorAxis(self, semiMajorAxis: float)¶
Inherited method. Use setRadius instead.
See also
See also
- Parameters:
semiMajorAxis (float) –
- setSemiMinorAxis(self, semiMinorAxis: float)¶
Inherited method. Use setRadius instead.
See also
See also
- Parameters:
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
andpt2
.Note that this method is 2D only and does not consider the z-value of the circle.
- Return type:
Tuple[bool,
QgsPointXY
, QgsPointXY]- Returns:
True
if tangent was found.
See also
New in version 3.2.
- Parameters:
p (QgsPointXY) –
- toCircularString(self, oriented: bool = False) QgsCircularString ¶
Returns a circular string from the circle.
- Parameters:
oriented (bool = False) – If oriented is
True
the start point is from azimuth instead from north.- Return type:
- toString(self, pointPrecision: int = 17, radiusPrecision: int = 17, azimuthPrecision: int = 2) str ¶
- Parameters:
pointPrecision (int = 17) –
radiusPrecision (int = 17) –
azimuthPrecision (int = 2) –
- Return type:
str