Question

I am using matplotlib to fit some data to a grid and plot it as a polar projection. Something like in the example below. However, I want it to be smooth where the edges of the plot meet at 0/360 degrees. Anyone know how I do this??

from pylab import *
import random

x = linspace(0, 360, 361).astype(int)
x = x*pi/180
y = linspace(0.05, 0.5, 800)
xgrid, ygrid = meshgrid(x, y)


baz = []
for c in range(2000): baz.append(random.randint(0,360))


freq = rand(len(baz))
pwr = rand(len(baz))

zgrid = griddata(baz,freq,pwr, xgrid, ygrid)
subplot(111,  polar=True)
pcolormesh(xgrid, ygrid, zgrid)
show()

Also the data I am working with has a gap due to the mask created by griddata (I use griddata as above but then sum many grids in a loop). I would like to fill the missing segment (see attached fig), does anyone know how to do this?

thanks
Dave

Answer 1

If you know which grids come together at the 0/360 degree position you could just concatenate them and do a spline interpolation on it (scipy interpolation).
For your second problem I am not sure but how about creating your grids in polar coordinates? Would this solve your problem?

Kind regards