legendgram method

[knaaptime]

for discussion

this moves the legendgram code into a method on the classifier class and tweaks it slightly so it can be used (traditionally) as an inset legend, or put in its own ax. If this is useful, we could probably swap the whole thing for the existing plot_histogram method

[codecov]

Codecov Report

Attention: Patch coverage is 11.11111% with 64 lines in your changes missing coverage. Please review.

Project coverage is 84.9%. Comparing base (e2613b5) to head (a421b4b).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
mapclassify/legendgram.py	4.5%	63 Missing ⚠️
mapclassify/classifiers.py	66.7%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #234     +/-   ##
=======================================
- Coverage   89.6%   84.9%   -4.7%     
=======================================
  Files          9      10      +1     
  Lines       1129    1200     +71     
=======================================
+ Hits        1012    1019      +7     
- Misses       117     181     +64     

Files with missing lines	Coverage Δ
mapclassify/__init__.py	100.0% <100.0%> (ø)
mapclassify/util.py	93.1% <100.0%> (+0.5%)	⬆️
mapclassify/classifiers.py	88.5% <66.7%> (-0.1%)	⬇️
mapclassify/legendgram.py	4.5% <4.5%> (ø)

[jGaboardi]

xref pysal/legendgram#21

[martinfleis]

If this is useful, we could probably swap the whole thing for the existing plot_histogram method

sounds great to me

[knaaptime]

one question (for @ljwolf maybe) is whether we can use bbox_to_anchor in addition to loc kwarg for moving stuff around in the _make_location function. For instance if I have

f, ax = plt.subplots(figsize=(8, 8))
gdf.plot(
    "HH_INC",
    scheme="quantiles",
    k=8,
    ax=ax,
    legend=True,
    legend_kwds={
        "bbox_to_anchor": (
            1.5,
            1,
        )
    },
)
c.plot_legendgram(ax=ax, loc="lower right", legend_size=(0.4, 0.3), inset=True)

it produces this figure, but i'd like to move the histogram beneath the legend using a similar bbox config

[martinfleis]

If we treat legend gram as inset axis and use Axes.inset_axes than you can move the axis in or out as you please, similarly to the placement of legend.