Draws a polygon on an existing plot.
Ngl.polygon(wks, plot, x, y, res=None)
The identifier returned from calling Ngl.open_wks.plot
The id of the plot which you want to draw the polygon on.x, y
One-dimensional (masked) NumPy arrays or Python lists containing the x, y coordinates of the polygon.res=None
An (optional) instance of the Resources class having GraphicStyle resources as attributes.
This function draws a polygon on the given plot. plot is the value returned from a previous call to one of the PyNGL plotting functions, like Ngl.xy, Ngl.contour_map, etc. x and y are 1-dimensional arrays (these can be Python lists or tuples, or NumPy arrays) defining the coordinates of the polygon, and resources can optionally contain an unlimited number of GraphicStyle attributes that are resource names and their values. Note that x and y must be in the same data space as the data in plot.
The frame is not advanced when you call this function, so you need to call Ngl.frame yourself if you want to advance the frame.
If you plan to resize your plot or use it in a call to Ngl.panel, then it is better to use the function Ngl.add_polygon. With this function, the polygon is attached to the plot and will automatically get resized when the plot is resized.