Fix and improvements to ImageStack

[hoxbro]

Fixes #5959 and fixes #5960

---

TODO:

• Think about the transpose problem The main problem is that a 2D Numpy array shape is defined as (y, x), not (x, y)
• Add tests
• Improve the docstring of hv.ImageStack

---

import holoviews as hv
import numpy as np
import panel as pn
import xarray as xr


hv.extension("bokeh")


p0 = hv.ImageStack(
    (np.arange(10), np.arange(15), np.arange(150).reshape(10, 15, 1))
).opts(num_colors=150, width=500)


p1 = hv.ImageStack(
    (np.arange(20, 30), np.arange(10, 20), np.arange(100).reshape(10, 10, 1))
).opts(num_colors=100, width=500)


p2 = hv.ImageStack(np.arange(100).reshape(10, 10, 1)).opts(num_colors=100, width=500)


da = xr.DataArray(coords={"x": np.arange(10), "y": np.arange(15)}, dims=["x", "y"])

da_1 = da.copy()
da_1.name = "a"
da_1.values = np.arange(150).reshape(10, 15)

ds = xr.merge([da_1])

p3 = hv.ImageStack(ds).opts(
    num_colors=140,
    width=500,
)

p = (p0 + p1 + p2 + p3).opts(shared_axes=False)

pn.panel(p).servable()

[codecov-commenter]

Codecov Report

Merging #5961 (93dce3a) into main (3adb998) will decrease coverage by 0.03%.
The diff coverage is 98.48%.

@@            Coverage Diff             @@
##             main    #5961      +/-   ##
==========================================
- Coverage   88.58%   88.55%   -0.03%     
==========================================
  Files         315      315              
  Lines       65500    65545      +45     
==========================================
+ Hits        58020    58046      +26     
- Misses       7480     7499      +19     

Flag	Coverage Δ
ui-tests	23.13% <4.54%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
holoviews/tests/plotting/bokeh/test_rasterplot.py	98.82% <100.00%> (+0.12%)	⬆️
holoviews/element/raster.py	80.30% <95.23%> (+0.30%)	⬆️

... and 2 files with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[hoxbro]

Added conversion of different inputs:

import holoviews as hv
import numpy as np

hv.extension("bokeh")

np.random.seed(42)
data = np.random.random((10, 15, 3))

p0 = hv.ImageStack(data)
p1 = hv.ImageStack([data[:, :, i] for i in range(3)])
p2 = hv.ImageStack({str(i): data[:, :, i] for i in range(3)})
p0 + p1 + p2

[hoxbro]

I'm not sure about the transposing, needs to think more about it.

With the following code:

import xarray as xr
import holoviews as hv
import numpy as np

hv.extension("bokeh")
x = np.arange(0, 3)
y = np.arange(5, 8)
a = np.array([[np.nan, np.nan, 1], [np.nan] * 3, [np.nan] * 3])
b = np.array([[np.nan] * 3, [1, 1, np.nan], [np.nan] * 3])
c = np.array([[np.nan] * 3, [np.nan] * 3, [1, 1, 1]])

ds = (x, y, a, b, c)
im_tuple = hv.ImageStack(ds).opts(title="Tuple")

ds = {"x": x, "y": y, "a": a, "b": b, "c": c}
im_dict = hv.ImageStack(ds).opts(title="Dict")

ds = xr.Dataset(
    {"a": (["x", "y"], a), "b": (["x", "y"], b), "c": (["x", "y"], c)},
    coords={"x": x, "y": y},
)
im_xr = hv.ImageStack(ds).opts(title="xarray")

im_tuple + im_dict + im_xr

I get this on the current branch:

And this on main:

[hoxbro]

This work on the current branch but not on main:

import xarray as xr
import holoviews as hv
import numpy as np

hv.extension("bokeh")
x = np.arange(0, 3)
y = np.arange(5, 9)
a = np.array([[np.nan, np.nan, 1, np.nan], [np.nan] * 4, [np.nan] * 4])
b = np.array([[np.nan] * 4, [1, 1, np.nan, np.nan], [np.nan] * 4])
c = np.array([[np.nan] * 4, [np.nan] * 4, [1, 1, 1, np.nan]])

ds = {"x": x, "y": y, "a": a, "b": b, "c": c}
im_dict = hv.ImageStack(ds).opts(title="Dict")

ds = xr.Dataset(
    {"a": (["x", "y"], a), "b": (["x", "y"], b), "c": (["x", "y"], c)},
    coords={"x": x, "y": y},
)
im_xr = hv.ImageStack(ds).opts(title="xarray")

im_dict + im_xr

[github-actions]

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