wradlib.vis.plot_cg_rhi

wradlib.vis.plot_cg_rhi(*args, **kwargs)

Plots a Range Height Indicator (RHI) on a curvelinear grid.

Deprecated since version 0.11.

Use plot_rhi

The implementation of this plot routine is in a curvelinear grid axes and does all coordinate transforms beforehand.

This allows zooming into the data as well as making it easier to plot additional cartesian data (like certain special points) without having to convert them to the radar’s polar coordinate system.

Plotting in the radar’s polar coordinate system is possible as well.

The function uses create_cg wich uses the Matplotlib AXISARTIST namespace mpl_toolkits.axisartist.

Here are some limitations to normal Matplotlib Axes. While using the Matplotlib AxesGrid Toolkit most of the limitations can be overcome. See Matplotlib AxesGrid Toolkit User’s Guide.

**kwargs may be used to try to influence matplotlib.pcolormesh under the hood.

Parameters:
  • data (np.array) – The data to be plotted. It is assumed that the first dimension is over the elevation angles, while the second dimension is over the range bins
  • r (np.array) – The ranges. Units may be chosen arbitrarily. If None, a default is calculated from the dimensions of data.
  • rf (float) – if present, factor for scaling range axis defaults to 1.
  • th (np.array) – The elevation angles in degrees. If None, a default is calculated from the dimensions of data and span from 0 to 90 degrees is assumed
  • th_res (float or np.array of same shape as th) – In RHI’s it happens that the elevation angles are spaced wider than the beam width. If this beam width (in degrees) is given in th_res, plot_rhi will plot the beams accordingly. Otherwise the behavior of matplotlib.pyplot.pcolormesh assumes all beams to be adjacent to each other, which might lead to unexpected results.
  • autoext (True | False) – This routine uses matplotlib.pyplot.pcolormesh to draw the bins. As this function needs one set of coordinates more than would usually provided by r and th, setting ´autoext´ to True automatically extends r and th so that all of data will be plotted.
  • refrac (True | False) – If True, the effect of refractivity of the earth’s atmosphere on the beam propagation will be taken into account. Functionality for this will be provided by functions wradlib.georef.arc_distance_n and wradlib.georef.beam_height_n, which assume distances to be given in meters. Therefore, if refrac is True, r must be given in meters. Cartesian Axis caax ist used for plotting. If False, PolarTransform will be used to calculate beam propagation.
  • fig (matplotlib Figure object) – If given, the RHI will be plotted into this figure object. Axes are created as needed. If None a new figure object will be created or current figure will be used, depending on “subplot”.
  • subplot (matplotlib grid definition) – nrows/ncols/plotnumber defaults to ‘111’, only one subplot

See also

create_cg
creation of curvelinear grid axes objects
Returns:
  • cgax (matplotlib Axes object) – curvelinear Axes (r-theta-grid)
  • caax (matplotlib Axes object) – Cartesian Axes (x-y-grid) for plotting cartesian data
  • paax (matplotlib Axes object) – The parasite axes object for plotting polar data All data in polar format must be plottet to this axis
  • pm (matplotlib QuadMesh object) – The result of the pcolormesh operation. Necessary, if you want to add a colorbar to the plot.

Examples

See Plot data to curvelinear grid.