Class: QgsTriangle¶

class qgis.core.QgsTriangle¶

Bases: qgis._core.QgsPolygon

QgsTriangle(p1: QgsPoint, p2: QgsPoint, p3: QgsPoint) Construct a QgsTriangle from three QgsPointV2.

Parameters

p1 – first point
p2 – second point
p3 – third point

QgsTriangle(p1: QgsPointXY, p2: QgsPointXY, p3: QgsPointXY) Construct a QgsTriangle from three QgsPoint.

Parameters

p1 – first point
p2 – second point
p3 – third point

QgsTriangle(p1: Union[QPointF, QPoint], p2: Union[QPointF, QPoint], p3: Union[QPointF, QPoint]) Construct a QgsTriangle from three QPointF.

Parameters

p1 – first point
p2 – second point
p3 – third point

QgsTriangle(QgsTriangle)

Triangle geometry type.

New in version 3.0: Enums

Methods

`addInteriorRing`	Inherited method not used.
`altitudes`	An altitude is a segment (defined by a `QgsLineString`) from a vertex to the opposite side (or, if necessary, to the extension of the opposite side).
`angles`	Returns the three angles of the triangle.
`asGml3`
`bisectors`	The segment (defined by a `QgsLineString`) returned bisect the angle of a vertex to the opposite side.
`boundary`
`calculateBoundingBox`
`childCount`
`childGeometry`
`childPoint`
`circumscribedCenter`	Center of the circumscribed circle of the triangle.
`circumscribedCircle`	Circumscribed circle of the triangle.
`circumscribedRadius`	Radius of the circumscribed circle of the triangle.
`clear`
`clearCache`
`clone`
`createEmptyWithSameType`
`deleteVertex`	Inherited method not used.
`fromWkb`
`fromWkt`
`geometryType`
`hasChildGeometries`
`inscribedCenter`	Center of the inscribed circle of the triangle.
`inscribedCircle`	Inscribed circle of the triangle.
`inscribedRadius`	Radius of the inscribed circle of the triangle.
`insertVertex`	Inherited method not used.
`isDegenerate`	Convenient method checking if the geometry is degenerate (have duplicate or colinear point(s)).
`isEquilateral`	Is the triangle equilateral (three sides with the same length)?
`isIsocele`	Is the triangle isocele (two sides with the same length)?
`isRight`	Is the triangle right-angled?
`isScalene`	Is the triangle scalene (all sides have different lengths)?
`lengths`	Returns the three lengths of the triangle.
`medial`	Medial (or midpoint) triangle of a triangle ABC is the triangle with vertices at the midpoints of the triangle’s sides.
`medians`	A median is a segment (defined by a `QgsLineString`) from a vertex to the midpoint of the opposite side.
`moveVertex`
`orthocenter`	An orthocenter is the point of intersection of the altitudes of a triangle.
`setExteriorRing`
`setZMTypeFromSubGeometry`
`surfaceToPolygon`
`toCurveType`
`vertexAt`	Returns coordinates of a vertex.

Signals

Attributes

addInteriorRing(self, ring: QgsCurve)¶: Inherited method not used. You cannot add an interior ring into a triangle.

altitudes(self) → List[QgsLineString]¶

An altitude is a segment (defined by a QgsLineString) from a vertex to the opposite side (or, if necessary, to the extension of the opposite side).

Returns: Three altitudes from this triangle. An empty list is returned for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
[alt.asWkt() for alt in tri.altitudes()]
# ['LineString (0 0, 0 5)', 'LineString (0 5, 2.5 2.5)', 'LineString (5 5, 0 5)']
QgsTriangle().altitudes()
# []

angles(self) → List[float]¶

Returns the three angles of the triangle.

Returns: Angles in radians of triangle ABC where angle BAC is at 0, angle ABC is at 1, angle BCA is at 2. An empty list is returned for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
[math.degrees(i) for i in tri.angles()]
# [45.0, 90.0, 45.0]
QgsTriangle().angles()
# []

asGml3(self, doc: QDomDocument, precision: int = 17, ns: str = '', axisOrder: QgsAbstractGeometry.AxisOrder = QgsAbstractGeometry.AxisOrder.XY) → QDomElement¶

bisectors(self, lengthTolerance: float = 0.0001) → List[QgsLineString]¶

The segment (defined by a QgsLineString) returned bisect the angle of a vertex to the opposite side.

Parameters: lengthTolerance – The tolerance to use.
Returns: Three angle bisector from this triangle. An empty list is returned for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
[bis.asWkt() for bis in tri.bisectors()]
# ['LineString (0 0, 2.07106781186547462 5)', 'LineString (0 5, 2.5 2.5)', 'LineString (5 5, 0 2.92893218813452538)']
QgsTriangle().bisectors()
# []

boundary(self) → QgsCurve¶

calculateBoundingBox()¶

childCount()¶

childGeometry()¶

childPoint()¶

circumscribedCenter(self) → QgsPoint¶

Center of the circumscribed circle of the triangle.

Returns: The center of the circumscribed circle of the triangle. An empty point is returned for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
tri.circumscribedCenter().asWkt()
# 'Point (2.5 2.5)'
QgsTriangle().circumscribedCenter().asWkt()
# 'Point (0 0)'

circumscribedCircle(self) → QgsCircle¶

Circumscribed circle of the triangle.

Returns: The circumbscribed of the triangle with a QgsCircle. An empty circle is returned for empty triangle. Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
tri.circumscribedCircle()
# QgsCircle(Point (2.5 2.5), 3.5355339059327378, 0)
QgsTriangle().circumscribedCircle()
# QgsCircle()

circumscribedRadius(self) → float¶

Radius of the circumscribed circle of the triangle.

Returns: The radius of the circumscribed circle of the triangle. 0.0 is returned for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
tri.circumscribedRadius()
# 3.5355339059327378
QgsTriangle().circumscribedRadius()
# 0.0

clear(self)¶

clearCache()¶

clone(self) → QgsTriangle¶

createEmptyWithSameType(self) → QgsTriangle¶

deleteVertex(self, position: QgsVertexId) → bool¶: Inherited method not used. You cannot delete or insert a vertex directly. Returns always False.

fromWkb(self, wkbPtr: QgsConstWkbPtr) → bool¶

fromWkt(self, wkt: str) → bool¶

geometryType(self) → str¶

hasChildGeometries()¶

inscribedCenter(self) → QgsPoint¶

Center of the inscribed circle of the triangle. Z dimension is supported and is retrieved from the first 3D point amongst vertices.

Returns: The center of the inscribed circle of the triangle. An empty point is returned for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
tri.inscribedCenter().asWkt()
# 'Point (1.46446609406726225 3.53553390593273775)'
QgsTriangle().inscribedCenter().asWkt()
# 'Point (0 0)'

inscribedCircle(self) → QgsCircle¶

Inscribed circle of the triangle.

Returns: The inscribed of the triangle with a QgsCircle. An empty circle is returned for empty triangle. Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
tri.inscribedCircle()
# QgsCircle(Point (1.46446609406726225 3.53553390593273775), 1.4644660940672622, 0)
QgsTriangle().inscribedCircle()
# QgsCircle()

inscribedRadius(self) → float¶

Radius of the inscribed circle of the triangle.

Returns: The radius of the inscribed circle of the triangle. 0.0 is returned for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
tri.inscribedRadius()
# 1.4644660940672622
QgsTriangle().inscribedRadius()
# 0.0

insertVertex(self, position: QgsVertexId, vertex: QgsPoint) → bool¶: Inherited method not used. You cannot delete or insert a vertex directly. Returns always False.

isDegenerate(self) → bool¶

Convenient method checking if the geometry is degenerate (have duplicate or colinear point(s)).

Returns: True if the triangle is degenerate or empty, otherwise False. Example:

tri = QgsTriangle()
tri.isDegenerate()
# True
tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
tri.isDegenerate()
# False
tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 5, 5 ), QgsPoint( 10, 10 ) )
tri.isDegenerate()
# True
tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 0 ), QgsPoint( 5, 5 ) )
tri.isDegenerate()
# True

isEquilateral(self, lengthTolerance: float = 0.0001) → bool¶

Is the triangle equilateral (three sides with the same length)?

Parameters: lengthTolerance – The tolerance to use
Returns: True or False. Always False for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 10, 10 ), QgsPoint( 16, 10 ), QgsPoint( 13, 15.1962 ) )
tri.lengths()
# [6.0, 6.0000412031918575, 6.0000412031918575]
tri.isEquilateral()
# True
# All lengths are close to 6.0
QgsTriangle().isEquilateral()
# False

isIsocele(self, lengthTolerance: float = 0.0001) → bool¶

Is the triangle isocele (two sides with the same length)?

Parameters: lengthTolerance – The tolerance to use
Returns: True or False. Always False for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
tri.lengths()
# [5.0, 5.0, 7.0710678118654755]
tri.isIsocele()
# True
# length of [AB] == length of [BC]
QgsTriangle().isIsocele()
# False

isRight(self, angleTolerance: float = 0.0001) → bool¶

Is the triangle right-angled?

Parameters: angleTolerance – The tolerance to use
Returns: True or False. Always False for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
[math.degrees(i) for i in tri.angles()]
# [45.0, 90.0, 45.0]
tri.isRight()
# True
# angle of ABC == 90
QgsTriangle().isRight()
# False

isScalene(self, lengthTolerance: float = 0.0001) → bool¶

Is the triangle scalene (all sides have different lengths)?

Parameters: lengthTolerance – The tolerance to use
Returns: True or False. Always False for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 7.2825, 4.2368 ), QgsPoint( 13.0058, 3.3218 ), QgsPoint( 9.2145, 6.5242 ) )
tri.lengths()
# [5.795980321740233, 4.962793714229921, 2.994131386562721]
tri.isScalene()
# True
# All lengths are different
QgsTriangle().isScalene()
# False

lengths(self) → List[float]¶

Returns the three lengths of the triangle.

Returns: Lengths of triangle ABC where [AB] is at 0, [BC] is at 1, [CA] is at 2. An empty list is returned for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
tri.lengths()
# [5.0, 5.0, 7.0710678118654755]
QgsTriangle().lengths()
# []

medial(self) → QgsTriangle¶

Medial (or midpoint) triangle of a triangle ABC is the triangle with vertices at the midpoints of the triangle’s sides.

Returns: The medial from this triangle. An empty triangle is returned for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
tri.medial().asWkt()
# 'Triangle ((0 2.5, 2.5 5, 2.5 2.5, 0 2.5))'
QgsTriangle().medial().asWkt()
# 'Triangle ( )'

medians(self) → List[QgsLineString]¶

A median is a segment (defined by a QgsLineString) from a vertex to the midpoint of the opposite side.

Returns: Three medians from this triangle. An empty list is returned for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
[med.asWkt() for med in tri.medians()]
# ['LineString (0 0, 2.5 5)', 'LineString (0 5, 2.5 2.5)', 'LineString (5 5, 0 2.5)']
QgsTriangle().medians()
# []

moveVertex(self, vId: QgsVertexId, newPos: QgsPoint) → bool¶

orthocenter(self, lengthTolerance: float = 0.0001) → QgsPoint¶

An orthocenter is the point of intersection of the altitudes of a triangle.

Parameters: lengthTolerance – The tolerance to use
Returns: The orthocenter of the triangle. An empty point is returned for empty triangle. * Example:

tri = QgsTriangle( QgsPoint( 0, 0 ), QgsPoint( 0, 5 ), QgsPoint( 5, 5 ) )
tri.orthocenter().asWkt()
# 'Point (0 5)'
QgsTriangle().orthocenter().asWkt()
# 'Point (0 0)'

setExteriorRing(self, ring: QgsCurve)¶

setZMTypeFromSubGeometry()¶

surfaceToPolygon(self) → QgsPolygon¶

toCurveType(self) → QgsCurvePolygon¶

vertexAt(self, atVertex: int) → QgsPoint¶

Returns coordinates of a vertex.

Parameters: atVertex – index of the vertex
Returns: Coordinates of the vertex or QgsPoint(0,0) on error (atVertex < 0 or > 3).