From 52c4727bd19afd5ea1dc9c3ecd6943b2284c75e0 Mon Sep 17 00:00:00 2001
From: Illviljan <14371165+Illviljan@users.noreply.github.com>
Date: Thu, 24 Jul 2025 18:48:52 +0200
Subject: [PATCH 1/6] simplify creating norms

---
 xarray/core/types.py          |  8 +++++--
 xarray/plot/dataarray_plot.py | 40 +++++++++++++++++------------------
 xarray/plot/dataset_plot.py   | 22 +++++++++----------
 xarray/plot/utils.py          | 30 ++++++++++++++++++++++----
 4 files changed, 63 insertions(+), 37 deletions(-)

diff --git a/xarray/core/types.py b/xarray/core/types.py
index 736a11f5f17..20b794e98e5 100644
--- a/xarray/core/types.py
+++ b/xarray/core/types.py
@@ -200,7 +200,9 @@ def copy(
 
 # FYI in some cases we don't allow `None`, which this doesn't take account of.
 # FYI the `str` is for a size string, e.g. "16MB", supported by dask.
-T_ChunkDim: TypeAlias = str | int | Literal["auto"] | tuple[int, ...] | None  # noqa: PYI051
+T_ChunkDim: TypeAlias = (
+    str | int | Literal["auto"] | tuple[int, ...] | None
+)  # noqa: PYI051
 T_ChunkDimFreq: TypeAlias = Union["TimeResampler", T_ChunkDim]
 T_ChunksFreq: TypeAlias = T_ChunkDim | Mapping[Any, T_ChunkDimFreq]
 # We allow the tuple form of this (though arguably we could transition to named dims only)
@@ -289,7 +291,9 @@ def copy(
 HueStyleOptions = Literal["continuous", "discrete"] | None
 AspectOptions = Union[Literal["auto", "equal"], float, None]
 ExtendOptions = Literal["neither", "both", "min", "max"] | None
-
+NormOptions = Literal[
+    "asinh", "function", "functionlog", "linear", "log", "logit", "symlog"
+]
 
 _T_co = TypeVar("_T_co", covariant=True)
 
diff --git a/xarray/plot/dataarray_plot.py b/xarray/plot/dataarray_plot.py
index 537fbd5bafb..110f69a2c84 100644
--- a/xarray/plot/dataarray_plot.py
+++ b/xarray/plot/dataarray_plot.py
@@ -866,7 +866,7 @@ def newplotfunc(
         cmap: str | Colormap | None = None,
         vmin: float | None = None,
         vmax: float | None = None,
-        norm: Normalize | None = None,
+        norm: NormOptions | Normalize | None = None,
         extend: ExtendOptions = None,
         levels: ArrayLike | None = None,
         **kwargs,
@@ -1142,7 +1142,7 @@ def scatter(  # type: ignore[misc,unused-ignore]  # None is hashable :(
     cmap: str | Colormap | None = None,
     vmin: float | None = None,
     vmax: float | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     extend: ExtendOptions = None,
     levels: ArrayLike | None = None,
     **kwargs,
@@ -1183,7 +1183,7 @@ def scatter(
     cmap: str | Colormap | None = None,
     vmin: float | None = None,
     vmax: float | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     extend: ExtendOptions = None,
     levels: ArrayLike | None = None,
     **kwargs,
@@ -1224,7 +1224,7 @@ def scatter(
     cmap: str | Colormap | None = None,
     vmin: float | None = None,
     vmax: float | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     extend: ExtendOptions = None,
     levels: ArrayLike | None = None,
     **kwargs,
@@ -1438,7 +1438,7 @@ def newplotfunc(
         yticks: ArrayLike | None = None,
         xlim: tuple[float, float] | None = None,
         ylim: tuple[float, float] | None = None,
-        norm: Normalize | None = None,
+        norm: NormOptions | Normalize | None = None,
         **kwargs: Any,
     ) -> Any:
         # All 2d plots in xarray share this function signature.
@@ -1692,7 +1692,7 @@ def imshow(  # type: ignore[misc,unused-ignore]  # None is hashable :(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> AxesImage: ...
 
@@ -1732,7 +1732,7 @@ def imshow(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> FacetGrid[T_DataArray]: ...
 
@@ -1772,7 +1772,7 @@ def imshow(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> FacetGrid[T_DataArray]: ...
 
@@ -1909,7 +1909,7 @@ def contour(  # type: ignore[misc,unused-ignore]  # None is hashable :(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> QuadContourSet: ...
 
@@ -1949,7 +1949,7 @@ def contour(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> FacetGrid[T_DataArray]: ...
 
@@ -1989,7 +1989,7 @@ def contour(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> FacetGrid[T_DataArray]: ...
 
@@ -2042,7 +2042,7 @@ def contourf(  # type: ignore[misc,unused-ignore]  # None is hashable :(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> QuadContourSet: ...
 
@@ -2082,7 +2082,7 @@ def contourf(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> FacetGrid[T_DataArray]: ...
 
@@ -2122,7 +2122,7 @@ def contourf(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> FacetGrid[T_DataArray]: ...
 
@@ -2175,7 +2175,7 @@ def pcolormesh(  # type: ignore[misc,unused-ignore]  # None is hashable :(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> QuadMesh: ...
 
@@ -2215,7 +2215,7 @@ def pcolormesh(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> FacetGrid[T_DataArray]: ...
 
@@ -2255,7 +2255,7 @@ def pcolormesh(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> FacetGrid[T_DataArray]: ...
 
@@ -2359,7 +2359,7 @@ def surface(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> Poly3DCollection: ...
 
@@ -2399,7 +2399,7 @@ def surface(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> FacetGrid[T_DataArray]: ...
 
@@ -2439,7 +2439,7 @@ def surface(
     yticks: ArrayLike | None = None,
     xlim: ArrayLike | None = None,
     ylim: ArrayLike | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     **kwargs: Any,
 ) -> FacetGrid[T_DataArray]: ...
 
diff --git a/xarray/plot/dataset_plot.py b/xarray/plot/dataset_plot.py
index ff508ee213c..97ac748d146 100644
--- a/xarray/plot/dataset_plot.py
+++ b/xarray/plot/dataset_plot.py
@@ -183,7 +183,7 @@ def newplotfunc(
         cmap: str | Colormap | None = None,
         vmin: float | None = None,
         vmax: float | None = None,
-        norm: Normalize | None = None,
+        norm: NormOptions | Normalize | None = None,
         infer_intervals: bool | None = None,
         center: float | None = None,
         robust: bool | None = None,
@@ -345,7 +345,7 @@ def quiver(  # type: ignore[misc,unused-ignore]  # None is hashable :(
     cbar_ax: Axes | None = None,
     vmin: float | None = None,
     vmax: float | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     infer_intervals: bool | None = None,
     center: float | None = None,
     levels: ArrayLike | None = None,
@@ -382,7 +382,7 @@ def quiver(
     cbar_ax: Axes | None = None,
     vmin: float | None = None,
     vmax: float | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     infer_intervals: bool | None = None,
     center: float | None = None,
     levels: ArrayLike | None = None,
@@ -419,7 +419,7 @@ def quiver(
     cbar_ax: Axes | None = None,
     vmin: float | None = None,
     vmax: float | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     infer_intervals: bool | None = None,
     center: float | None = None,
     levels: ArrayLike | None = None,
@@ -496,7 +496,7 @@ def streamplot(  # type: ignore[misc,unused-ignore]  # None is hashable :(
     cbar_ax: Axes | None = None,
     vmin: float | None = None,
     vmax: float | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     infer_intervals: bool | None = None,
     center: float | None = None,
     levels: ArrayLike | None = None,
@@ -533,7 +533,7 @@ def streamplot(
     cbar_ax: Axes | None = None,
     vmin: float | None = None,
     vmax: float | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     infer_intervals: bool | None = None,
     center: float | None = None,
     levels: ArrayLike | None = None,
@@ -570,7 +570,7 @@ def streamplot(
     cbar_ax: Axes | None = None,
     vmin: float | None = None,
     vmax: float | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     infer_intervals: bool | None = None,
     center: float | None = None,
     levels: ArrayLike | None = None,
@@ -783,7 +783,7 @@ def scatter(  # type: ignore[misc,unused-ignore]  # None is hashable :(
     cmap: str | Colormap | None = None,
     vmin: float | None = None,
     vmax: float | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     extend: ExtendOptions = None,
     levels: ArrayLike | None = None,
     **kwargs: Any,
@@ -824,7 +824,7 @@ def scatter(
     cmap: str | Colormap | None = None,
     vmin: float | None = None,
     vmax: float | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     extend: ExtendOptions = None,
     levels: ArrayLike | None = None,
     **kwargs: Any,
@@ -865,7 +865,7 @@ def scatter(
     cmap: str | Colormap | None = None,
     vmin: float | None = None,
     vmax: float | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     extend: ExtendOptions = None,
     levels: ArrayLike | None = None,
     **kwargs: Any,
@@ -906,7 +906,7 @@ def scatter(
     cmap: str | Colormap | None = None,
     vmin: float | None = None,
     vmax: float | None = None,
-    norm: Normalize | None = None,
+    norm: NormOptions | Normalize | None = None,
     extend: ExtendOptions = None,
     levels: ArrayLike | None = None,
     **kwargs: Any,
diff --git a/xarray/plot/utils.py b/xarray/plot/utils.py
index a71613562a5..5fe5de41c6d 100644
--- a/xarray/plot/utils.py
+++ b/xarray/plot/utils.py
@@ -44,7 +44,7 @@
 
     from xarray.core.dataarray import DataArray
     from xarray.core.dataset import Dataset
-    from xarray.core.types import AspectOptions, ScaleOptions
+    from xarray.core.types import AspectOptions, ScaleOptions, NormOptions
 
     try:
         import matplotlib.pyplot as plt
@@ -58,6 +58,26 @@
 _LINEWIDTH_RANGE = (1.5, 1.5, 6.0)
 
 
+def _make_norm_from_string(
+    norm: NormOptions,
+) -> type[Normalize]:
+    """
+    Get norm from string.
+
+    Examples
+    --------
+    >>> _make_norm_from_string("log")
+    <class 'matplotlib.colors.LogScaleNorm'>
+
+    """
+    from matplotlib.colors import make_norm_from_scale, Normalize
+    from matplotlib.scale import scale_factory
+
+    scale = type(scale_factory(norm, None))  # type: ignore [arg-type] # mpl issue, use of ax is discouraged
+
+    return make_norm_from_scale(scale, Normalize)
+
+
 def _determine_extend(calc_data, vmin, vmax):
     extend_min = calc_data.min() < vmin
     extend_max = calc_data.max() > vmax
@@ -264,6 +284,8 @@ def _determine_cmap_params(
 
     # now check norm and harmonize with vmin, vmax
     if norm is not None:
+        norm = _make_norm_from_string(norm)() if isinstance(norm, str) else norm
+
         if norm.vmin is None:
             norm.vmin = vmin
         else:
@@ -278,9 +300,9 @@ def _determine_cmap_params(
                 raise ValueError("Cannot supply vmax and a norm with a different vmax.")
             vmax = norm.vmax
 
-    # if BoundaryNorm, then set levels
-    if isinstance(norm, mpl.colors.BoundaryNorm):
-        levels = norm.boundaries
+        # if BoundaryNorm, then set levels
+        if isinstance(norm, mpl.colors.BoundaryNorm):
+            levels = norm.boundaries
 
     # Choose default colormaps if not provided
     if cmap is None:

From af31fcb07f311aaecb9b8e58df6f78a8e0193a9f Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Thu, 24 Jul 2025 16:51:04 +0000
Subject: [PATCH 2/6] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 xarray/core/types.py | 4 +---
 xarray/plot/utils.py | 4 ++--
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/xarray/core/types.py b/xarray/core/types.py
index 20b794e98e5..2a3918c838b 100644
--- a/xarray/core/types.py
+++ b/xarray/core/types.py
@@ -200,9 +200,7 @@ def copy(
 
 # FYI in some cases we don't allow `None`, which this doesn't take account of.
 # FYI the `str` is for a size string, e.g. "16MB", supported by dask.
-T_ChunkDim: TypeAlias = (
-    str | int | Literal["auto"] | tuple[int, ...] | None
-)  # noqa: PYI051
+T_ChunkDim: TypeAlias = str | int | Literal["auto"] | tuple[int, ...] | None
 T_ChunkDimFreq: TypeAlias = Union["TimeResampler", T_ChunkDim]
 T_ChunksFreq: TypeAlias = T_ChunkDim | Mapping[Any, T_ChunkDimFreq]
 # We allow the tuple form of this (though arguably we could transition to named dims only)
diff --git a/xarray/plot/utils.py b/xarray/plot/utils.py
index 5fe5de41c6d..753d85ab280 100644
--- a/xarray/plot/utils.py
+++ b/xarray/plot/utils.py
@@ -44,7 +44,7 @@
 
     from xarray.core.dataarray import DataArray
     from xarray.core.dataset import Dataset
-    from xarray.core.types import AspectOptions, ScaleOptions, NormOptions
+    from xarray.core.types import AspectOptions, NormOptions, ScaleOptions
 
     try:
         import matplotlib.pyplot as plt
@@ -70,7 +70,7 @@ def _make_norm_from_string(
     <class 'matplotlib.colors.LogScaleNorm'>
 
     """
-    from matplotlib.colors import make_norm_from_scale, Normalize
+    from matplotlib.colors import Normalize, make_norm_from_scale
     from matplotlib.scale import scale_factory
 
     scale = type(scale_factory(norm, None))  # type: ignore [arg-type] # mpl issue, use of ax is discouraged

From 2ad69cf92ed7cd4b311be001ca3d49317ca5aee6 Mon Sep 17 00:00:00 2001
From: Illviljan <14371165+Illviljan@users.noreply.github.com>
Date: Sat, 26 Jul 2025 20:29:49 +0200
Subject: [PATCH 3/6] import also

---
 xarray/plot/dataarray_plot.py | 1 +
 xarray/plot/dataset_plot.py   | 1 +
 2 files changed, 2 insertions(+)

diff --git a/xarray/plot/dataarray_plot.py b/xarray/plot/dataarray_plot.py
index 110f69a2c84..5e8878dc952 100644
--- a/xarray/plot/dataarray_plot.py
+++ b/xarray/plot/dataarray_plot.py
@@ -50,6 +50,7 @@
         AspectOptions,
         ExtendOptions,
         HueStyleOptions,
+        NormOptions,
         ScaleOptions,
         T_DataArray,
     )
diff --git a/xarray/plot/dataset_plot.py b/xarray/plot/dataset_plot.py
index 97ac748d146..21641312022 100644
--- a/xarray/plot/dataset_plot.py
+++ b/xarray/plot/dataset_plot.py
@@ -30,6 +30,7 @@
         AspectOptions,
         ExtendOptions,
         HueStyleOptions,
+        NormOptions,
         ScaleOptions,
     )
     from xarray.plot.facetgrid import FacetGrid

From 8bdf1f4a97720137cca0ab14b5cc44a6b8918828 Mon Sep 17 00:00:00 2001
From: Illviljan <14371165+Illviljan@users.noreply.github.com>
Date: Sat, 26 Jul 2025 21:13:15 +0200
Subject: [PATCH 4/6] Update xarray/core/types.py

---
 xarray/core/types.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xarray/core/types.py b/xarray/core/types.py
index 2a3918c838b..a1226c643b7 100644
--- a/xarray/core/types.py
+++ b/xarray/core/types.py
@@ -200,7 +200,7 @@ def copy(
 
 # FYI in some cases we don't allow `None`, which this doesn't take account of.
 # FYI the `str` is for a size string, e.g. "16MB", supported by dask.
-T_ChunkDim: TypeAlias = str | int | Literal["auto"] | tuple[int, ...] | None
+T_ChunkDim: TypeAlias = str | int | Literal["auto"] | tuple[int, ...] | None  # noqa: PYI051
 T_ChunkDimFreq: TypeAlias = Union["TimeResampler", T_ChunkDim]
 T_ChunksFreq: TypeAlias = T_ChunkDim | Mapping[Any, T_ChunkDimFreq]
 # We allow the tuple form of this (though arguably we could transition to named dims only)

From 26753b7af8d7d2fbcac826ea733e32bc3754309f Mon Sep 17 00:00:00 2001
From: Illviljan <14371165+Illviljan@users.noreply.github.com>
Date: Sat, 26 Jul 2025 21:17:04 +0200
Subject: [PATCH 5/6] Update xarray/plot/utils.py

---
 xarray/plot/utils.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/xarray/plot/utils.py b/xarray/plot/utils.py
index 753d85ab280..2cc457d7c09 100644
--- a/xarray/plot/utils.py
+++ b/xarray/plot/utils.py
@@ -300,9 +300,9 @@ def _determine_cmap_params(
                 raise ValueError("Cannot supply vmax and a norm with a different vmax.")
             vmax = norm.vmax
 
-        # if BoundaryNorm, then set levels
-        if isinstance(norm, mpl.colors.BoundaryNorm):
-            levels = norm.boundaries
+    # if BoundaryNorm, then set levels
+     if isinstance(norm, mpl.colors.BoundaryNorm):
+        levels = norm.boundaries
 
     # Choose default colormaps if not provided
     if cmap is None:

From e0833b3a378c1d9506528c0ed02e83e0778b61ae Mon Sep 17 00:00:00 2001
From: Illviljan <14371165+Illviljan@users.noreply.github.com>
Date: Sat, 26 Jul 2025 21:17:47 +0200
Subject: [PATCH 6/6] Update xarray/plot/utils.py

---
 xarray/plot/utils.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xarray/plot/utils.py b/xarray/plot/utils.py
index 2cc457d7c09..cef035dbfb6 100644
--- a/xarray/plot/utils.py
+++ b/xarray/plot/utils.py
@@ -301,7 +301,7 @@ def _determine_cmap_params(
             vmax = norm.vmax
 
     # if BoundaryNorm, then set levels
-     if isinstance(norm, mpl.colors.BoundaryNorm):
+    if isinstance(norm, mpl.colors.BoundaryNorm):
         levels = norm.boundaries
 
     # Choose default colormaps if not provided