Colors for discrete ranges in heatmaps

đź“Š Plotly Python
2

@heff The heatmap trace selects the color from a colorscale, according to the normalized values in the lists of lists z (or a numpy array of shape (m,n)).

The discrete colorscale should be defined as follows:

  • find the max value for z, let us say that it is 125:

  • map the interval [0, max_val] to [0,1] by t--> t/max_val

  • mapping your thresholds [0, 10, 50, 100, 125] to [0,1], you get
    [0, 0.08, 0.4, 0.8, 1].

  • define the discrete colorscale:

    my_colorsc=[[0, 'rgb(255,255,255)'],#white
            [0.08, 'rgb(255,255,255'], 
            [0.08, 'rgb(255,165,0)'],#orange
            [0.4, 'rgb(255,165,0)'],
            [0.4, 'rgb(255,0,0'], #red
            [0.8, 'rgb(255,0,0)'],
            [0.8, 'rgb(0,0,255)'], #blue
            [1, 'rgb(0,0,255)']]

Plotly doesn’t recognize cmyk colors.

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