# obspy.taup.slowness_model.SlownessModel.layer_time_dist

`SlownessModel.``layer_time_dist`(spherical_ray_param, layer_num, is_p_wave, check=True, allow_turn=False)

  Calculate time and distance for a ray passing through a layer.

  Calculates the time and distance increments accumulated by a ray of spherical ray parameter `p` when passing through layer `layer_num`. Note that this gives half of the true range and time increments since there will be both an upgoing and a downgoing path. It also only does the calculation for the simple cases of the centre of the planet, where the ray parameter is zero, or for constant velocity layers. Otherwise, it calls `bullen_radial_slowness()`.

  Either `spherical_ray_param` or `layer_num` must be 0-D, or they must have the same shape.

  Parameters: | spherical_ray_param (`float` or `ndarray`) The spherical ray parameter of the ray(s), in s/km. layer_num (`float` or `ndarray`) The layer(s) in which the calculation should be done. is_p_wave (bool) Whether to look at the P (`True`) or S (`False`) wave. check (bool) Whether to perform checks of input consistency. allow_turn (bool) Whether to allow the ray to turn in the middle of a layer.
  Returns: | The time (in s) and distance (in rad) increments for the specified ray(s) and layer(s).
  Return type: | `ndarray` (dtype = `TimeDist`, shape = `spherical_ray_param.shape` or `layer_num.shape`)
  Raises SlownessModelError:
  | If the ray with the given spherical ray parameter cannot propagate within this layer, or if the ray turns within this layer but not at the bottom. These checks may be bypassed by specifying `check=False`.

### Thank you!

We would like to thank our contributors, whose efforts make this software what it is. These people have helped by writing code and documentation, and by testing. They have created and maintained this product, its associated libraries and applications, our build tools and our web sites.

#### Contributors

- Ackerley, Nick
- Allgeyer, Sebastien
- Ammon, Charles J.
- Antunes, Emanuel
- Arnarsson, Ólafur St.
- Bank, Markus
- Barsch, Robert
- Behr, Yannik
- Bernardi, Fabrizio
- Bernauer, Felix
- Bes de Berc, Maxime
- Beyreuther, Moritz
- Boltz, Shawn
- Bonaimé, Sébastien
- Carothers, Lloyd
- Chamberlain, Calum
- Chambers, Derrick
- Chen, Zhao
- Clark, Adam
- Danecek, Peter
- Egdorf, Sven
- Engels, Fabian
- Ermert, Laura
- Eulenfeld, Tom

- Fabbri, Tommaso
- Falco, Nicholas
- Fee, Jeremy
- Grellier, Clément
- Grunberg, Marc
- Hammer, Conny
- Heimann, Sebastian
- Heiniger, Lukas
- Hope, Gaute
- Igel, Heiner
- Inza, Adolfo
- Isken, Marius
- Ketchum, David
- Koymans, Mathijs
- Kremers, Simon
- Kress, Victor
- Krieger, Lars
- Krischer, Lion
- Kula, Damian
- Käufl, Paul
- Köhler, Andreas
- Lecocq, Thomas
- Leeman, John
- Legovini, Paride

- Lesage, Philippe
- Li, Yulin
- Lomax, Anthony
- Lopes, Rui L.
- MacCarthy, Jonathan
- Maggi, Alessia
- Martin, Henri
- Medlin, Andrew
- Megies, Tobias
- Meschede, Matthias
- Michelini, Alberto
- Miller, Nathaniel C.
- Morgenstern, Bernhard
- Nof, Ran Novitsky
- Panning, Mark P.
- Parker, Tom
- Pestourie, Romain
- Rapagnani, Giovanni
- Reyes, Celso
- Ringler, Adam
- Rothenhäusler, Nicolas
- Russo, Emiliano
- Sales de Andrade, Elliott

- Satriano, Claudio
- Saul, Joachim
- Scheingraber, Chris
- Schneider, Simon
- Sippl, Christian
- Snoke, Arthur
- Stange, Stefan
- Stähler, Simon C.
- Sullivan, Benjamin
- Tian, Dongdong
- Trabant, Chad
- Trani, Luca
- Uieda, Leonardo
- Walker, Andrew
- Walther, Marcus
- Wassermann, Joachim
- Williams, Mark C.
- Winkelman, Andrew
- Zaccarelli, Riccardo
- Zad, Seyed Kasra Hosseini
- Zhu, Lijun
- van Driel, Martin
- van Wijk, Kasper

#### Funds

ObsPy was partially funded by the

- German Science Foundation (DFG) via grant DFG IG 16/9-1
- German Ministry for Education and Research (BMBF), GEOTECHNOLOGIEN grant 03G0646H.
- NERA project (Network of European Research Infrastructures for Earthquake Risk Assessment and Mitigation) under the European Community's Seventh Framework Programme (FP7/2007-2013) grant agreement n° 262330
- Leibniz Institute for Applied Geophysics (LIAG)
- VERCE EU-FP7 project (no. 283543)