[Matplotlib-users] Displaying raster colormap in a colorbar

[Benjamin Root]

Well, why are you creating an RGB array?. Why not just pass the data into
imshow() and give it vmin/vmax and the colormap that you'd like to use?

On Fri, Aug 3, 2018 at 5:26 PM, Matthew Bradley <mbatr27 at gmail.com> wrote:

> Here's a basic mockup of what I'm running into:
>
> import matplotlib.pyplot as plt
> import numpy as np; np.random.seed(1)
>
> example_2D = np.random.rand(841,138)
>
> example_raster = np.empty([example_2D.shape[0],example_2D.shape[1],3])
> for i in range(example_2D.shape[0]):
>     for j in range(example_2D.shape[1]):
>         if example_2D[i,j] < 0.5:
>             example_raster[i,j] = [0,example_2D[i,j],0]
>         else:
>             example_raster[i,j] = [example_2D[i,j],0,0]
>
> fig, ax = plt.subplots(figsize=(4,4))
>
> im = ax.imshow(example_raster, aspect='auto')
>
> fig.colorbar(im, orientation="horizontal")
> plt.show()
>
> There is a ipynb file attached for anyone who wants to play around with it.
>
>
>
> @ Bruno and Benjamin: Yes, that's essentially what I am doing. Here in
> this simple example I'm just doctoring it so that I get red and green
> values but in the actual dataset there are negative values that I set to be
> green and all the positive values are red
>
> On Fri, Aug 3, 2018 at 3:14 PM, Bruno Pagani <bruno.pagani at astrophysics.eu
> > wrote:
>
>> Le 03/08/2018 à 23:09, Benjamin Root a écrit :
>> > I think the issue is that the user is passing in an RGB array, but
>> > wants a colormap that matches that array. That is a bit tricky. Do I
>> > have my understanding correct?
>> >
>> > Ben
>>
>> Exactly what I understood too. So do you have a solution for this? I’ve
>> stackoverflow’d that question a bit, nothing cames out.
>>
>> Bruno
>>
>
>
>
> --
> Matthew Bradley
>
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