$LastChangedDate: 27-Juil-2011 $

# CL_plot_ephem

Plots ground tracks

## Calling Sequence

       CL_plot_ephem(pos_car [,win_id,color_id,tick_steps,data_bounds,thickness])

## Description

- Plots the ground track in longitude and latitude corresponding to the trajectory given in cartesian coordinates.

  The plot x-axis and y-axis are respectively the (spherical) longitude and latitude in degrees.

  These longitude and latitude are obtained from pos_car by: [lon; lat; r] = CL_co_car2sph(pos_car).

## Parameters

pos_car:

  Positions in cartesian coordinates: [X;Y;Z] (3xN)

win_id:

  (optional) Figure Id - Id of the current window if omitted.

color_id:

  (optional) Color index - Default is 2.

tick_steps:

  (optional) Steps of the grid in longitude and latitude in degrees. Default is [60 ,30].

data_bounds:

  (optional) Definition of the view area: [longmin, latmin; longmax, latmax] in degrees. Default is [-180, -90; 180, 90].

thickness:

  (optional) Line thickness. Default is 1.

## Authors

- CNES - DCT/SB

## See also

- CL_plot_earthMap

## Examples

    t0 = 21915; // initial time
    kep_t0=[7070.e3; 0.001; CL_deg2rad(98); 0; 0; 0]; // orbit parameters
    step = 30 / 86400; // propagation step
    t = t0:step:t0+1;
    kep_t = CL_ex_secularJ2(t0, kep_t0, t); // orbit propagation

    pos_eci = CL_oe_kep2car(kep_t);      // inertial position
    pos_ecf = CL_fr_G502ter(t, pos_eci); // position in rotating frame

    scf();
    CL_plot_ephem(pos_ecf);
    CL_plot_earthMap();