[Matplotlib-users] Displaying raster colormap in a colorbar

[Matthew Bradley]

Nice solution, I wasn't thinking in those sorts of terms before but I think
that is the way to go!

Thanks!

On Fri, Aug 3, 2018 at 3:39 PM, Benjamin Root <ben.v.root at gmail.com> wrote:

> 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
>>
>
>


-- 
Matthew Bradley
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