Fix matplotlib>=3.9 compatibility: replace removed plt.cm.get_cmap - #205
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matplotlib deprecated `matplotlib.cm.get_cmap` in 3.7 and removed it in
3.9, so on newer matplotlib (reproduced on 3.11) any colormap export
raised:
AttributeError: module 'matplotlib.cm' has no attribute 'get_cmap'
This broke `python -m pingmapper test` during sonogram tile export
(sonObj._colorize_array_batched) and would also break the rectification
colormap path (rectObj) and the substrate summary plot.
Replace every `plt.cm.get_cmap(...)` call with the still-supported
`plt.get_cmap(...)` (matplotlib.pyplot.get_cmap), a drop-in that also
handles a None colormap name like the old API. The already-valid
`matplotlib.colormaps.get_cmap(...)` calls are left unchanged.
Verified by running `python -m pingmapper test` (small dataset) through
the full read -> rectify -> substrate pipeline to completion on
matplotlib 3.11.
Fixes CameronBodine#203.
Co-authored-by: HuggeK <48095810+HuggeK@users.noreply.github.com>
HuggeK
marked this pull request as ready for review
July 29, 2026 13:48
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Summary
Fixes #203.
On matplotlib 3.9+, running the test dataset (
python -m pingmapper test) crashes during sonogram tile export with:matplotlib.cm.get_cmapwas deprecated in matplotlib 3.7 and removed in 3.9. PINGMapper calls it asplt.cm.get_cmap(...)in several colormap paths, so any environment with a current matplotlib (reproduced here on 3.11) fails as soon as it reaches sonogram/rectified-tile colorizing.Fix
Replace every
plt.cm.get_cmap(...)with the still-supportedplt.get_cmap(...)(matplotlib.pyplot.get_cmap). This is a minimal drop-in: it returns the sameColormapobject, is not deprecated in current matplotlib, and — like the old API — gracefully handles aNonecolormap name. The already-validmatplotlib.colormaps.get_cmap(...)calls inclass_rectObj.pyare left untouched.pingmapper/class_sonObj.py_colorize_array_batched, the crash in #203)pingmapper/class_rectObj.pypingmapper/class_mapSubstrateObj.pypingmapper/class_sonObj_nadirgaptest.pyTesting
Ran
python -m pingmapper test(small dataset) on matplotlib 3.11 — the full read → rectify → substrate pipeline now runs to completion, including the previously-failing "Exporting sonogram tiles" stage.Why
plt.get_cmaprather thanmatplotlib.colormaps[name]Both work, but
plt.get_cmap(name)is the smallest possible change fromplt.cm.get_cmap(name)(just drop.cm), keeps the exact same call signature, and preserves the old behavior of acceptingNone(returns the default colormap) — whereasmatplotlib.colormaps[None]raisesKeyError.pltis already imported in every affected module, so no import changes are needed. It also matches the existingcolormaps.get_cmap(...)usage already present inclass_rectObj.py.🤖 Generated with Claude Code