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retistruct (version 0.5.9)

flipped.triangles: Determine indicies of triangles that are flipped

Description

In the projection of points onto the sphere, some triangles maybe flipped, i.e. in the wrong orientation. This functions determines which triangles are flipped by computing the vector pointing to the centre of each triangle and comparing this direction to vector product of two sides of the triangle.

Usage

flipped.triangles(phi, lambda, Tt, R)

Arguments

phi
Vector of lattitudes of points
lambda
Vector of longitudes of points
Tt
Triangulation of points
R
Radius of sphere

Value

  • List containing:
  • flippedIndicies of in rows of Tt of flipped triangles.
  • centsVectors of centres.
  • areasAreas of triangles.