pygplates.NetworkTriangulation

class pygplates.NetworkTriangulation

Bases: instance

The Delaunay triangulation of a resolved topological network.

This is the triangulation of the convex hull of the vertices obtained from the network’s resolved boundary (polygon), and any interior rigid blocks (polygons) and any interior geometries (points or lines).

See also

Network triangulation in the Primer documentation.

Added in version 0.50.

get_adjacent_triangle(index)

Returns the triangle adjacent to this triangle that is opposite the vertex at the specified index.

Parameters:: index (int) – the index of this triangle’s vertex (in the range [0, 2])
Returns:: the adjacent network triangle, or None if the triangle edge that is opposite the vertex at index is a boundary edge of the network triangulation (ie, a convex hull edge)
Return type:: NetworkTriangulation.Triangle or None
Raises:: ValueError if index is not in the range [0, 2]

To access the three adjacent triangles of a triangle in a network triangulation:

for index in range(3):
   triangle_opposite_vertex_at_index = triangle.get_adjacent_triangle(index)
   if triangle_opposite_vertex_at_index:  # if not at a triangulation boundary
       ...

get_vertex(index)

Returns one of this triangle’s three vertices.

Parameters:: index (int) – the index of this triangle’s vertex (in the range [0, 2])
Return type:: NetworkTriangulation.Vertex
Raises:: ValueError if index is not in the range [0, 2]

To access the three vertices of a triangle in a network triangulation:

for index in range(3):
   triangle_vertex = triangle.get_vertex(index)

property is_in_deforming_region

Whether this triangle is in the deforming region of the network.

Type:: bool

Note

A triangle is in the deforming region if its centroid is in the deforming region (where the deforming region is defined to be inside the network’s boundary polygon but outside any interior rigid block polygons).

property strain_rate

Return the constant strain rate across this triangle.

Type:: StrainRate

Note

This will be pygplates.StrainRate.zero if this triangle is not deforming.

class Vertex

Bases: instance

A vertex in a network triangulation.

Vertices are equality (==, !=) comparable and hashable (can be used as a key in a dict).

See also

Network triangulation in the Primer documentation.

Added in version 0.50.

get_incident_triangles()

Returns the triangles incident to this vertex.

Return type:: list of NetworkTriangulation.Triangle

get_incident_vertices()

Returns the vertices incident to this vertex.

Return type:: list of NetworkTriangulation.Vertex

get_velocity([velocity_delta_time=1.0][, velocity_delta_time_type=pygplates.VelocityDeltaTimeType.t_plus_delta_t_to_t][, velocity_units=pygplates.VelocityUnits.kms_per_my][, earth_radius_in_kms=pygplates.Earth.mean_radius_in_kms])

Returns the velocity of this vertex.

Parameters:

velocity_delta_time (float) – The time delta used to calculate velocity (defaults to 1 Myr).
velocity_delta_time_type (VelocityDeltaTimeType.t_plus_delta_t_to_t, VelocityDeltaTimeType.t_to_t_minus_delta_t or VelocityDeltaTimeType.t_plus_minus_half_delta_t) – How the two velocity times are calculated relative to the reconstruction time. This includes [t+dt, t], [t, t-dt] and [t+dt/2, t-dt/2]. Defaults to [t+dt, t].
velocity_units (VelocityUnits.kms_per_my or VelocityUnits.cms_per_yr) – whether to return velocity as kilometres per million years or centimetres per year (defaults to kilometres per million years)
earth_radius_in_kms (float) – the radius of the Earth in kilometres (defaults to pygplates.Earth.mean_radius_in_kms)

Return type:

Vector3D

Raises:

ValueError if velocity_delta_time is negative or zero.

property position

Return the position of this vertex.

Type:: PointOnSphere

property strain_rate

Return the strain rate at this vertex.

Type:: StrainRate

Note

This is the area-averaged strain rate of deforming triangles incident to this vertex.

get_triangles()

Returns a read-only sequence of the triangles in this triangulation.

Return type:: a read-only sequence of NetworkTriangulation.Triangle

The following operations for accessing the triangles in the returned read-only sequence are supported:

Operation	Result
`len(seq)`	number of triangles in the triangulation
`for t in seq`	iterates over the triangles t in the triangulation
`seq[i]`	the triangle in the triangulation at index i

The following example demonstrates some uses of the above operations:

network_triangulation = resolved_topological_network.get_network_triangulation()
triangles = network_triangulation.get_triangles()

for triangle in triangles:
    ...

num_triangles = len(triangles)
for triangle_index in range(num_triangles):
   triangle = triangles[triangle_index]

Note

The returned sequence is read-only and cannot be modified.

get_vertices()

Returns a read-only sequence of the vertices in this triangulation.

Return type:: a read-only sequence of NetworkTriangulation.Vertex

The following operations for accessing the vertices in the returned read-only sequence are supported:

Operation	Result
`len(seq)`	number of vertices in the triangulation
`for v in seq`	iterates over the vertices v in the triangulation
`seq[i]`	the vertex in the triangulation at index i

The following example demonstrates some uses of the above operations:

network_triangulation = resolved_topological_network.get_network_triangulation()
vertices = network_triangulation.get_vertices()

for vertex in vertices:
    ...

num_vertices = len(vertices)
for vertex_index in range(num_vertices):
   vertex = vertices[vertex_index]

Note

The returned sequence is read-only and cannot be modified.

`__init__`	Raises an exception This class cannot be instantiated from Python
`get_triangles`	Returns a read-only sequence of the triangles in this triangulation.
`get_vertices`	Returns a read-only sequence of the vertices in this triangulation.