wradlib.vis.plot_cg_ppi

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

Plots a Plan Position Indicator (PPI) on a curvelinear grid.

Deprecated since version 0.11.

Use plot_ppi

The implementation of this plot routine is in curvelinear grid axes and does all coordinate transforms beforehand. This allows zooming into the data as well as making it easier to plot additional data (like gauge locations).

Additional data can be plotted in polar coordinates or cartesian coordinates depending which axes object is used.

The function uses create_cg which 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 the matplotlib.pcolormesh routine under the hood.

Parameters:
  • data (np.array) – The data to be plotted. It is assumed that the first dimension is over the azimuth 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.
  • az (np.array) – The azimuth angles in degrees. If None, a default is calculated from the dimensions of data.
  • 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 be provided by r and az, setting ´autoext´ to True automatically extends r and az 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. If False, simple trigonometry will be used to calculate beam propagation. Functionality for this will be provided by function wradlib.georef.arc_distance_n. Therefore, if refrac is True, r must be given in meters.
  • elev (float or array of same shape as az) – Elevation angle of the scan or individual azimuths. May improve georeferencing coordinates for larger elevation angles.
  • fig (matplotlib Figure object) – If given, the PPI 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, gridspec definition) – nrows/ncols/plotnumber, see examples section defaults to ‘111’, only one subplot

See also

create_cg
creation of curvelinear grid axes objects
Returns:
  • cgax (matplotlib toolkit axisartist Axes object) – Curvelinear Axes (r-theta-grid)
  • caax (matplotlib Axes object (twin to cgax)) – Cartesian Axes (x-y-grid) for plotting cartesian data
  • paax (matplotlib Axes object (parasite to cgax)) – The parasite axes object for plotting polar data all data in polar format must be plotted 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.