Class: QgsTriangle¶

Triangle geometry type.

Class Hierarchy¶

Base classes¶

`QgsPolygon`	Polygon geometry type.
`QgsCurvePolygon`	Curve polygon geometry type.
`QgsSurface`	Surface geometry type.
`QgsAbstractGeometry`	Abstract base class for all geometries.

Abstract Methods

`deleteVertex`	Inherited method not used.
`insertVertex`	Inherited method not used.
`vertexAt`

Methods

`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.
`bisectors`	The segment (defined by a `QgsLineString`) returned bisect the angle of a vertex to the opposite side.
`circumscribedCenter`	Center of the circumscribed circle of the triangle.
`circumscribedCircle`	Circumscribed circle of the triangle.
`circumscribedRadius`	Radius of the circumscribed circle of the triangle.
`inscribedCenter`	Center of the inscribed circle of the triangle.
`inscribedCircle`	Inscribed circle of the triangle.
`inscribedRadius`	Radius of the inscribed circle of the triangle.
`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.
`orthocenter`	An orthocenter is the point of intersection of the altitudes of a triangle.

Virtual Methods

In PyQGIS, only methods marked as virtual can be safely overridden in a Python subclass of QgsTriangle. See the FAQ for more details.

addInteriorRing

Inherited method not used.

class qgis.core.QgsTriangle[source]¶

Bases: QgsPolygon

__init__(): Constructor for an empty triangle geometry.

__init__(p1: QgsPoint, p2: QgsPoint, p3: QgsPoint)

Construct a QgsTriangle from three QgsPoint.

Parameters:

p1 (QgsPoint) – first point
p2 (QgsPoint) – second point
p3 (QgsPoint) – third point

__init__(p1: QgsPointXY, p2: QgsPointXY, p3: QgsPointXY)

Construct a QgsTriangle from three QgsPointXY.

Parameters:

p1 (QgsPointXY) – first point
p2 (QgsPointXY) – second point
p3 (QgsPointXY) – third point

__init__(p1: QPointF | QPoint, p2: QPointF | QPoint, p3: QPointF | QPoint)

Construct a QgsTriangle from three QPointF.

Parameters:

p1 (Union[QPointF, QPoint]) – first point
p2 (Union[QPointF, QPoint]) – second point
p3 (Union[QPointF, QPoint]) – third point

__init__(a0: QgsTriangle)

Parameters:: a0 (QgsTriangle)

virtual addInteriorRing(self, ring: QgsCurve | None)[source]¶

Inherited method not used. You cannot add an interior ring into a triangle.

Parameters:: ring (Optional[QgsCurve])

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).

Return type:: List[QgsLineString]
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.

Return type:: List[float]
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()
# []

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 (float = 0.0001) – The tolerance to use.
Return type:: List[QgsLineString]
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()
# []

circumscribedCenter(self) → QgsPoint[source]¶

Center of the circumscribed circle of the triangle.

Return type:: QgsPoint
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[source]¶

Circumscribed circle of the triangle.

Return type:: QgsCircle
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[source]¶

Radius of the circumscribed circle of the triangle.

Return type:: float
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

abstract deleteVertex(self, position: QgsVertexId) → bool[source]¶

Inherited method not used. You cannot delete or insert a vertex directly. Returns always False.

Parameters:: position (QgsVertexId)
Return type:: bool

inscribedCenter(self) → QgsPoint[source]¶

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

Return type:: QgsPoint
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[source]¶

Inscribed circle of the triangle.

Return type:: QgsCircle
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[source]¶

Radius of the inscribed circle of the triangle.

Return type:: float
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

abstract insertVertex(self, position: QgsVertexId, vertex: QgsPoint) → bool[source]¶

Inherited method not used. You cannot delete or insert a vertex directly. Returns always False.

Parameters:

position (QgsVertexId)
vertex (QgsPoint)

Return type:

bool

isDegenerate(self) → bool[source]¶

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

Return type:: bool
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[source]¶

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

Parameters:: lengthTolerance (float = 0.0001) – The tolerance to use
Return type:: bool
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[source]¶

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

Parameters:: lengthTolerance (float = 0.0001) – The tolerance to use
Return type:: bool
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[source]¶

Is the triangle right-angled?

Parameters:: angleTolerance (float = 0.0001) – The tolerance to use
Return type:: bool
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[source]¶

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

Parameters:: lengthTolerance (float = 0.0001) – The tolerance to use
Return type:: bool
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.

Return type:: List[float]
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[source]¶

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

Return type:: QgsTriangle
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.

Return type:: List[QgsLineString]
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()
# []

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

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

Parameters:: lengthTolerance (float = 0.0001) – The tolerance to use
Return type:: QgsPoint
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)'

abstract vertexAt(self, id: QgsVertexId) → QgsPoint[source]¶

Parameters:: id (QgsVertexId)
Return type:: QgsPoint

abstract vertexAt(self, atVertex: int) → QgsPoint[source]

Returns coordinates of a vertex.

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