Add numpy 2.5 compatibility

Start by reproducing the reported conda-forge installation with basemap and NumPy 2.5, then compare the dependency constraints that cause NumPy, pyshp, and packaging to be downgraded. Done means basemap can be installed in a recent environment without downgrading NumPy; the issue mentions no repository files or tests to start from.

I guess this is some kind of follow-up of #647 , as requested by @thebaptiste

Note: I'm using conda and everything (including conda) from conda-forge

I have tried several times this week to add basemap to a fairly complex (but up-to-date) Python environment, and had to kill conda because nothing happened. That is conda install was not moving anymore, but the conda process was using more and more resources. This time, I killed a 100% CPU conda process using 13 Gb after 200 minutes

So I tried to install only basemap, with conda create -n basemap_test basemap in order to check I could install it at all! This worked perfectly and quickly, but I ended up with numpy 2.3.5 (not numpy 2.4)

If conda was not working with my complex environment, I thought I would use mamba again, which I have not done since mamba became the default solver of conda. And I quickly got a result (no mamba deadlock or guru meditation)!! Trouble is that mamba wants to downgrade the installed numpy, which is a no-go. And also wants to downgrade pyshp (and packaging) but I don't know anything about these

  Package                     Version  Build            Channel           Size
────────────────────────────────────────────────────────────────────────────────
  Install:
────────────────────────────────────────────────────────────────────────────────

  + basemap                     2.0.0  py312h8d133b9_5  conda-forge      189kB
  + basemap-data                2.0.0  basemap_0        conda-forge     Cached

  Downgrade:
────────────────────────────────────────────────────────────────────────────────

  - numpy                       2.5.3  py312he827f4e_0  conda-forge     Cached
  + numpy                       2.3.5  py312h33ff503_1  conda-forge        9MB
  - numpy-typing-compat  20260602.2.5  pyhb860519_1     conda-forge     Cached
  + numpy-typing-compat  20260602.2.3  pyhc46ce56_1     conda-forge       13kB
  - packaging                    26.3  pyhc364b38_0     conda-forge     Cached
  + packaging                    25.0  pyh29332c3_1     conda-forge     Cached
  - pyshp                       3.1.6  pyhcf101f3_0     conda-forge     Cached
  + pyshp                       2.3.1  pyhd8ed1ab_1     conda-forge     Cached

  Summary:

  Install: 2 packages
  Downgrade: 4 packages

Any thoughts on that, by somebody who knows about packages dependencies and constraints?

Note that the environment where I installed only basemap has pyshp 2.3.1. Could the problem come from pyshp?

Full list of the basemap-only environment below

I have asked the student who wanted basemap to use cartopy instead, so this is not a blocking problem. But it would be nice to still be able to install basemap in a recent environment, if it does not require too much work from the people in charge :-)

(base) $ conda list -n basemap_test
# packages in environment at /home/share/unix_files/cdat/miniconda3_2024-03/envs/basemap_test:
#
# Name                     Version          Build                 Channel
_openmp_mutex              4.5              20_gnu                conda-forge
basemap                    2.0.0            py314h9620088_5       conda-forge
basemap-data               2.0.0            basemap_0             conda-forge
brotli                     1.2.0            h505cf86_4            conda-forge
brotli-bin                 1.2.0            h9908984_4            conda-forge
bzip2                      1.0.8            hda65f42_10           conda-forge
c-ares                     1.34.8           hebe6cf0_2            conda-forge
ca-certificates            2026.7.22        hbd8a1cb_0            conda-forge
certifi                    2026.7.22        pyhd8ed1ab_0          conda-forge
contourpy                  1.4.0            py314h5383ef5_1       conda-forge
cycler                     0.12.1           pyhcf101f3_2          conda-forge
fonttools                  4.66.0           py314hd42368d_0       conda-forge
freetype                   2.14.3           ha770c72_2            conda-forge
geos                       3.14.1           h55b0958_0            conda-forge
icu                        78.3             py310h44b86e0_2       conda-forge
keyutils                   1.6.3            h7cc23a3_1            conda-forge
kiwisolver                 1.5.1            py314h5383ef5_3       conda-forge
krb5                       1.22.2           hbc21106_2            conda-forge
lcms2                      2.19.1           h9073bf1_3            conda-forge
ld_impl_linux-64           2.46.1           default_hbd61a6d_102  conda-forge
lerc                       4.2.0            hdb68285_0            conda-forge
libblas                    3.11.0           11_h4a7cf45_openblas  conda-forge
libbrotlicommon            1.2.0            h39a168f_4            conda-forge
libbrotlidec               1.2.0            ha411449_4            conda-forge
libbrotlienc               1.2.0            h018ffa1_4            conda-forge
libcblas                   3.11.0           11_h0358290_openblas  conda-forge
libcurl                    8.22.0           ha042cf0_0            conda-forge
libdeflate                 1.25             hd45a770_1            conda-forge
libedit                    3.1.20250104     pl5321h373387f_1      conda-forge
libev                      4.33             h280c20c_3            conda-forge
libexpat                   2.8.4            hd2095e1_0            conda-forge
libffi                     3.7.0            h81df57d_1            conda-forge
libfreetype                2.14.3           ha770c72_2            conda-forge
libfreetype6               2.14.3           h5e6c136_2            conda-forge
libgcc                     16.2.0           ha9f2e26_7            conda-forge
libgcc-ng                  16.2.0           h69a702a_7            conda-forge
libgfortran                16.2.0           h69a702a_7            conda-forge
libgfortran5               16.2.0           h6b99dfc_7            conda-forge
libgomp                    16.2.0           he0feb66_7            conda-forge
libjpeg-turbo              3.2.0            hb03c661_1            conda-forge
liblapack                  3.11.0           11_h47877c9_openblas  conda-forge
liblzma                    5.8.3            hb03c661_1            conda-forge
libmpdec                   4.0.0            hb03c661_2            conda-forge
libnghttp2                 1.68.1           h74cf4be_1            conda-forge
libopenblas                0.3.34           pthreads_hf13c14d_2   conda-forge
libpng                     1.6.58           h922cc85_1            conda-forge
libpsl                     0.23.1           hd9e3e90_1            conda-forge
libpython                  3.14.7           hdc7f604_106_cp314    conda-forge
libsqlite                  3.53.4           h13e7031_1            conda-forge
libssh2                    1.11.1           h6154650_1            conda-forge
libstdcxx                  16.2.0           h934c35e_7            conda-forge
libstdcxx-ng               16.2.0           hdf11a46_7            conda-forge
libtiff                    4.7.2            hcc2c06a_1            conda-forge
libuuid                    2.42.4           hcfc3c73_0            conda-forge
libwebp-base               1.6.0            hd42ef1d_1            conda-forge
libxcb                     1.17.0           hb83e432_2            conda-forge
libzlib                    1.3.2            h25fd6f3_3            conda-forge
matplotlib-base            3.10.9           py314h1194b4b_0       conda-forge
munkres                    1.1.4            pyhd8ed1ab_1          conda-forge
ncurses                    6.6              hdb14827_1            conda-forge
numpy                      2.3.5            py314h2b28147_1       conda-forge
openjpeg                   2.5.4            heb1ab33_2            conda-forge
openssl                    3.6.4            h781a0a9_0            conda-forge
packaging                  25.0             pyh29332c3_1          conda-forge
pillow                     12.3.0           py314h50bfbbb_4       conda-forge
pip                        26.2.1           pyh145f28c_0          conda-forge
proj                       9.8.1            he0df7b0_0            conda-forge
pthread-stubs              0.4              h7cc23a3_1004         conda-forge
pyparsing                  3.3.3            pyh5ded981_0          conda-forge
pyproj                     3.7.2            py314hf1f854a_5       conda-forge
pyshp                      2.3.1            pyhd8ed1ab_1          conda-forge
python                     3.14.7           hcd007b5_106_cp314    conda-forge
python-dateutil            2.9.0.post0      pyhe01879c_2          conda-forge
python_abi                 3.14             9_cp314               conda-forge
qhull                      2020.2           h434a139_5            conda-forge
readline                   8.3              hd6e31c0_1            conda-forge
six                        1.17.0           pyhe01879c_1          conda-forge
sqlite                     3.53.4           h9ffa6c4_1            conda-forge
tk                         8.6.13           noxft_h1df4ec4_4      conda-forge
tzdata                     2026c            h151e31d_0            conda-forge
xorg-libxau                1.0.12           h7cc23a3_2            conda-forge
xorg-libxdmcp              1.1.5            h7cc23a3_2            conda-forge
zlib-ng                    2.3.3            hce19668_1            conda-forge
zstd                       1.5.7            hb78ec9c_7            conda-forge