def average_linestrings(line1: QgsLineString,
line2: QgsLineString,
weight: float = 1) -> QgsLineString:
"""
Averages two linestring geometries
"""
g1 = line1.clone()
# project points from g2 onto g1
for n in range(line2.numPoints()):
vertex = line2.pointN(n)
_, pt, after, _ = g1.closestSegment(vertex)
g1.insertVertex(QgsVertexId(0, 0, after.vertex), pt)
# iterate through vertices in g1
out = []
for n in range(g1.numPoints()):
vertex = g1.pointN(n)
_, pt, after, _ = line2.closestSegment(vertex)
# average pts
x = (vertex.x() * weight + pt.x()) / (weight + 1)
y = (vertex.y() * weight + pt.y()) / (weight + 1)
out.append(QgsPoint(x, y))
return QgsLineString(out)
def qgslinestring_angle(linestring: QgsLineString, point: QgsPoint):
"""
Calculate angle of a QgsLineString at specified QgsPoint.
"""
distance, closest_point, vertex_id, left_of = linestring.closestSegment(point)
"""
print(
distance,
closest_point,
linestring.vertexNumberFromVertexId(vertex_id),
left_of
)
"""
p1 = linestring.pointN(linestring.vertexNumberFromVertexId(vertex_id) - 1)
p2 = linestring.pointN(linestring.vertexNumberFromVertexId(vertex_id))
return vector_angle(p1, p2)
