# ARTS built-in documentation server

## Workspace Method ppathCalc

### Description

Stand-alone calculation of propagation paths. Beside a few checks of input data, the only operation of this method is to execute ppath_agenda. Propagation paths are normally calculated as part of the radiative transfer calculations, and this method is not part of the control file. A reason to call this function directly would be to obtain a propagation path for plotting. Anyhow, use this method instead of calling e.g.*ppathStepByStep directly.

**Authors: **Patrick Eriksson

### Synopsis

ppathCalc( | ppath, ppath_agenda, ppath_lmax, ppath_lraytrace, atmgeom_checked, f_grid, cloudbox_on, cloudbox_checked, ppath_inside_cloudbox_do, rte_pos, rte_los, rte_pos2 ) |

### Variables

OUT | ppath | (Ppath) | The propagation path for one line-of-sight. |

IN | ppath_agenda | (Agenda) | Agenda calculating complete propagation paths. |

IN | ppath_lmax | (Numeric) | Maximum length between points describing propagation paths. |

IN | ppath_lraytrace | (Numeric) | Maximum length of ray tracing steps when determining propagation paths. |

IN | atmgeom_checked | (Index) | OK-flag for the geometry of the model atmosphere. |

IN | f_grid | (Vector) | The frequency grid for monochromatic pencil beam calculations. |

IN | cloudbox_on | (Index) | Flag to activate the cloud box. |

IN | cloudbox_checked | (Index) | OK-flag for variables associated with the cloudbox. |

IN | ppath_inside_cloudbox_do | (Index) | Flag to perform ray tracing inside the cloudbox. |

IN | rte_pos | (Vector) | A geographical position for starting radiative transfer calculations. |

IN | rte_los | (Vector) | A line-of-sight for (complete) radiative transfer calculations. |

IN | rte_pos2 | (Vector) | A second geographical position to define the geometry for radiative transfer calculations. |