ntw_to_r

ssapy.utils.ntw_to_r(r, v, ntw, relative=False)[source][source]

Convert NTW coordinates to cartesian coordinates, using r, v to define NTW system.

T gives the projection of (rcoord - r) along V (tangent to track) W gives the projection of (rcoord - r) along (V cross r) (normal to plane) N gives the projection of (rcoord - r) along (V cross (V cross r))

(in plane, perpendicular to T)

Parameters:

  • r (array_like (n, 3)) – central positions defining coordinate system

  • v (array_like (n, 3)) – velocity defining coordinate system

  • ntw (array_like (n, 3)) – ntw coordinates to transform to cartesian coordinates

  • relative (bool) – if True, just rotate the NTW coordinates to Cartesian; do not offset the origin so that NTW = 0 -> Cartesian r.

Returns:

r – cartesian x, y, z coordinates

Return type:

array_like (n, 3)