CODEWITHSUNDEEP
pythonbokeh
wxcoder
wxcoder

Reputation: 655

Plot showing up black in Bokeh

I am trying to plot radar data in bokeh from an hdf5 file. I've stored the data into a 2d array that is 1800*3600. When I try to plot the data using p.image it shows up black with some splotches which i'm assuming is where the data is greater than 0, but it doesn't conform to the palette i've specified. I'm not sure why this is occurring. 

f = h5py.File(fname, 'r')
lat = f['Grid']['lat']
lon = f['Grid']['lon']
precip = f['Grid']['precipitationCal']
precip = np.transpose(precip)

d = np.empty((1800,3600))
for (x,y), value in np.ndenumerate(precip):
    if value <= 0:
        d[x,y]=np.nan
    else:
        d[x,y]=value


output_file("testimage.html", title="image.py example")
p = figure(x_range = [0, 3600], y_range=[0, 1800])
p.image(image=[d],x=[0],y=[0],dw=[3600], dh=[1800], pallete="Spectral-256")
show(p)

enter image description here

Upvotes: 1

Views: 510

Answers (1)

Luke Canavan
Luke Canavan

Reputation: 2137

Two things:

First, the argument to pass to p.image is spelled "palette" not "pallete". The default palette is Grey9, which would give you the colormap you have.

Second (and the docs are sort of unclear on this), the palette argument accepts a list containing the colormap as hex values. This can be either an arbitrary list:

palette = ["#8c9494", "#8398a2", "#7c9baa"] 
p.image(image=[d],x=[0],y=[0],dw=[360], dh=[180], palette=palette)

or a standard palette from Bokeh

from bokeh.palettes import Spectral6
p.image(image=[d],x=[0],y=[0],dw=[360], dh=[180], palette=Spectral6)

Note:

print(Spectral6)
> ['#3288bd', '#99d594', '#e6f598', '#fee08b', '#fc8d59', '#d53e4f']

https://docs.bokeh.org/en/latest/docs/reference/palettes.html

Upvotes: 1

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