Refactor dependencies to make more optional

docs/getting-started/installation.rst

@@ -23,8 +23,8 @@ To install UXarray with its recommended dependencies using the conda command lin
 
 .. note::
 
-   Conda automatically installs Xarray and every other required
-   dependency (including non‑Python libraries).
+   Conda automatically installs Xarray, all other required depdencies,
+   and all optional dependencies too (including non‑Python libraries).
 
 Installing with pip
 -------------------
@@ -37,11 +37,16 @@ This installs the *minimal* required dependencies. UXarray also provides optiona
 .. code-block:: bash
 
    pip install "uxarray[dev]"       # development tools
+   pip install "uxarray[geo]"       # geospatial tools (e.g. geopandas, healpix)
+   pip install "uxarray[viz]"       # plotting tools (e.g. matplotlib, hvplot)
    pip install "uxarray[complete]"  # all optional features
 
-A complete list of extras lives in the ``[project.optional-dependencies]``
+A complete list of optional dependencies lives in the ``[project.optional-dependencies]``
 section of our `pyproject.toml <https://github.com/UXARRAY/uxarray/blob/main/pyproject.toml>`_
 
+Optional extras can also be combined, e.g. ``pip install "uxarray[geo,viz]"`` installs with
+all required dependencies plus all optional dependencies for geospatial and plotting tools.
+
 
 Installing from source
 ----------------------
@@ -67,7 +72,7 @@ Installing from source is intended mainly for developers.
 
    .. code-block:: bash
 
-      pip install .
+      pip install ".[complete]"   # test suite relies on optional dependencies
 
 #. **Run the test suite**
 

pyproject.toml

@@ -23,35 +23,45 @@ requires-python = ">=3.10"
 # minimal dependencies start
 dependencies = [
   "antimeridian",
-  "cartopy",
   "dask[dataframe]",
-  "datashader",
-  "geoviews",
-  "holoviews",
-  "matplotlib<3.11",  # matplotlib 3.11.0 breaks some plots but <3.11 is fine; see issue #1542.
-  "matplotlib-inline",
   "netcdf4",
   "numba>=0.63",  # 0.63 is the first release supporting Python 3.14 (3.10 <= py < 3.15). See #1561.
   "numpy",
   "pandas",
-  "pyarrow",
-  "requests",
   "scikit-learn",
   "scipy",
   "shapely",
-  "spatialpandas",
-  "geopandas",
   "xarray",
-  "hvplot",
-  "healpix",
   "polars",
-  "pyproj"
 ]
 # minimal dependencies end
 
 [project.optional-dependencies]
-complete = ["uxarray[dev]"]
-dev = ['pre_commit', 'pytest', 'pytest-cov', 'ruff', 'asv']
+all = ["uxarray[dev,geo,viz]"]
+complete = ["uxarray[dev,geo,viz]"]  # alias to "all"
+dev = [
+    'asv',
+    'pooch',
+    'pre_commit',
+    'pytest',
+    'pytest-cov',
+    'ruff',
+]
+geo = [
+    "cartopy",  # in both geo and viz it is needed by to_geodataframe() and by plotting routines.
+    "geopandas",
+    "healpix",
+    "pyproj",
+    "spatialpandas",
+]
+viz = [
+    "cartopy",
+    "datashader",
+    "matplotlib<3.11",  # matplotlib 3.11.0 breaks some plots but <3.11 is fine; see issue #1542.
+    "geoviews",
+    "holoviews",
+    "hvplot",
+]
 
 [project.urls]
 Documentation = "https://uxarray.readthedocs.io/"

uxarray/plot/accessor.py

@@ -472,6 +472,9 @@ def polygons(
             project=False,
         )
 
+        # import datashader  # no need to import explicitly, but gets used below when rasterize=True.
+        # (commented here for future reference, since datashader appears in uxarray dependency list,
+        #    but it isn't imported explicitly anywhere in uxarray. For more details see PR #1548.)
         return gdf.hvplot.polygons(
             c=self._uxda.name if self._uxda.name is not None else "var",
             rasterize=rasterize,