Add Scene function to use Hvplot backend visualization

AUTHORS.md

@@ -50,6 +50,7 @@ The following people have made contributions to this project:
 - [Lu Liu (yukaribbba)](/~https://github.com/yukaribbba)
 - [Andrea Meraner (ameraner)](/~https://github.com/ameraner)
 - [Aronne Merrelli (aronnem)](/~https://github.com/aronnem)
+- [Luca Merucci (lmeru)](/~https://github.com/lmeru)
 - [Lucas Meyer (LTMeyer)](/~https://github.com/LTMeyer)
 - [Zifeng Mo (Isotr0py)](/~https://github.com/Isotr0py)
 - [Ondrej Nedelcev (nedelceo)](/~https://github.com/nedelceo)

continuous_integration/environment.yaml

@@ -37,11 +37,12 @@ dependencies:
   - mock
   - libtiff
   - geoviews
+  - holoviews
+  - hvplot
   - zarr
   - python-eccodes
   # 2.19.1 seems to cause library linking issues
   - eccodes>=2.20
-  - geoviews
   - pytest
   - pytest-cov
   - pytest-lazy-fixture

doc/source/conf.py

@@ -70,7 +70,7 @@ def __getattr__(cls, name):
 for mod_name in MOCK_MODULES:
     sys.modules[mod_name] = Mock()  # type: ignore
 
-autodoc_mock_imports = ["cf", "glymur", "h5netcdf", "imageio", "mipp", "netCDF4",
+autodoc_mock_imports = ["cf", "glymur", "h5netcdf", "holoviews", "imageio", "mipp", "netCDF4",
                         "pygac", "pygrib", "pyhdf", "pyninjotiff",
                         "pyorbital", "pyspectral", "rasterio", "trollimage",
                         "zarr"]

satpy/scene.py

@@ -1,4 +1,4 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 # Copyright (c) 2010-2022 Satpy developers
 #
@@ -28,7 +28,7 @@
 from pyresample.geometry import AreaDefinition, BaseDefinition, SwathDefinition
 from xarray import DataArray
 
-from satpy.composites import IncompatibleAreas
+from satpy.composites import IncompatibleAreas, enhance2dataset
 from satpy.composites.config_loader import load_compositor_configs_for_sensors
 from satpy.dataset import DataID, DataQuery, DatasetDict, combine_metadata, dataset_walker, replace_anc
 from satpy.dependency_tree import DependencyTree
@@ -1066,6 +1066,80 @@
 
         return gview
 
+    def to_hvplot(self, datasets=None, *args, **kwargs):
+        """Convert satpy Scene to Hvplot. The method could not be used with composites of swath data.
+
+        Args:
+            datasets (list): Limit included products to these datasets.
+            args: Arguments coming from hvplot
+            kwargs: hvplot options dictionary.
+
+        Returns: hvplot object that contains within it the plots of datasets list.
+                 As default it contains all Scene datasets plots and a plot title is shown.
+
+        Example usage::
+
+           scene_list = ['ash','IR_108']
+           scn = Scene()
+           scn.load(scene_list)
+           scn = scn.resample('eurol')
+           plot = scn.to_hvplot(datasets=scene_list)
+           plot.ash+plot.IR_108
+        """
+
+        def _get_crs(xarray_ds):
+            return xarray_ds.area.to_cartopy_crs()
+
+        def _get_timestamp(xarray_ds):
+            time = xarray_ds.attrs["start_time"]
+            return time.strftime("%Y %m %d -- %H:%M UTC")
+
+        def _get_units(xarray_ds, variable):
+            return xarray_ds[variable].attrs["units"]
+
+        def _plot_rgb(xarray_ds, variable, **defaults):
+            img = enhance2dataset(xarray_ds[variable])
+            return img.hvplot.rgb(bands="bands", title=title,
+                                  clabel="", **defaults)
+
+        def _plot_quadmesh(xarray_ds, variable, **defaults):
+            return xarray_ds[variable].hvplot.quadmesh(
+                clabel=f"[{_get_units(xarray_ds,variable)}]", title=title,
+                **defaults)
+
+        import hvplot.xarray as hvplot_xarray  # noqa
+        from holoviews import Overlay
+
+        plot = Overlay()
+        xarray_ds = self.to_xarray_dataset(datasets)
+
+        if hasattr(xarray_ds, "area") and hasattr(xarray_ds.area, "to_cartopy_crs"):
+            ccrs = _get_crs(xarray_ds)
+            defaults={"x":"x","y":"y"}
+        else:
+            ccrs = None
+            defaults={"x":"longitude","y":"latitude"}
+
+        if datasets is None:
+            datasets = list(xarray_ds.keys())
+
+        defaults.update(data_aspect=1, project=True, geo=True,
+                        crs=ccrs, projection=ccrs, rasterize=True, coastline="110m",
+                        cmap="Plasma", responsive=True, dynamic=False, framewise=True,
+                        colorbar=False, global_extent=False, xlabel="Longitude",
+                        ylabel="Latitude")
+
+        defaults.update(kwargs)
+
+        for element in datasets:
+            title = f"{element} @ {_get_timestamp(xarray_ds)}"
+            if xarray_ds[element].shape[0] == 3:
+                plot[element] = _plot_rgb(xarray_ds, element, **defaults)
+            else:
+                plot[element] = _plot_quadmesh(xarray_ds, element, **defaults)
+
+        return plot
+
     def to_xarray_dataset(self, datasets=None):
         """Merge all xr.DataArrays of a scene to a xr.DataSet.
 

satpy/tests/scene_tests/test_conversions.py

@@ -81,6 +81,53 @@
         # we assume that if we got something back, geoviews can use it
         assert gv_obj is not None
 
+    def test_hvplot_basic_with_area(self):
+        """Test converting a Scene to hvplot with a AreaDefinition."""
+        from pyresample.geometry import AreaDefinition
+        scn = Scene()
+        area = AreaDefinition("test", "test", "test",
+                              {"proj": "geos", "lon_0": -95.5, "h": 35786023.0},
+                              2, 2, [-200, -200, 200, 200])
+        scn["ds1"] = xr.DataArray(da.zeros((2, 2), chunks=-1), dims=("y", "x"),
+                                  attrs={"start_time": datetime(2018, 1, 1),
+                                         "area": area, "units": "m"})
+        hv_obj = scn.to_hvplot()
+        # we assume that if we got something back, hvplot can use it
+        assert hv_obj is not None
+
+    def test_hvplot_rgb_with_area(self):
+        """Test converting a Scene to hvplot with a AreaDefinition."""
+        from pyresample.geometry import AreaDefinition
+        scn = Scene()
+        area = AreaDefinition("test", "test", "test",
+                              {"proj": "geos", "lon_0": -95.5, "h": 35786023.0},
+                              2, 2, [-200, -200, 200, 200])
+        scn["ds1"] = xr.DataArray(da.zeros((2, 2), chunks=-1), dims=("y", "x"),
+                                  attrs={"start_time": datetime(2018, 1, 1),
+                                         "area": area, "units": "m"})
+        scn["ds2"] = xr.DataArray(da.zeros((2, 2), chunks=-1), dims=("y", "x"),
+                                  attrs={"start_time": datetime(2018, 1, 1),
+                                         "area": area, "units": "m"})
+        scn["ds3"] = xr.DataArray(da.zeros((2, 2), chunks=-1), dims=("y", "x"),
+                                  attrs={"start_time": datetime(2018, 1, 1),
+                                         "area": area, "units": "m"})
+        hv_obj = scn.to_hvplot()
+        # we assume that if we got something back, hvplot can use it
+        assert hv_obj is not None
+
+    def test_hvplot_basic_with_swath(self):
+        """Test converting a Scene to hvplot with a SwathDefinition."""
+        from pyresample.geometry import SwathDefinition
+        scn = Scene()
+        longitude = xr.DataArray(da.zeros((2, 2)))
+        latitude = xr.DataArray(da.zeros((2, 2)))
+        area = SwathDefinition(longitude, latitude)
+        scn["ds1"] = xr.DataArray(da.zeros((2, 2), chunks=-1), dims=("y", "x"),
+                                  attrs={"start_time": datetime(2018, 1, 1),
+                                         "area": area, "units": "m"})
+        hv_obj = scn.to_hvplot()
+        # we assume that if we got something back, hvplot can use it
+        assert hv_obj is not None
 
 class TestToXarrayConversion:
     """Test Scene.to_xarray() conversion."""
@@ -161,6 +208,6 @@
 
     def test_to_xarray_with_multiple_area_scene(self, multi_area_scn):
         """Test converting muiltple area Scene to xarray."""
         # TODO: in future adapt for DataTree implementation
         with pytest.raises(ValueError, match="Datasets to be saved .* must have identical projection coordinates."):
             _ = multi_area_scn.to_xarray()

setup.py

@@ -76,6 +76,8 @@
     "doc": ["sphinx", "sphinx_rtd_theme", "sphinxcontrib-apidoc"],
     # Other
     "geoviews": ["geoviews"],
+    "holoviews": ["holoviews"],
+    "hvplot": ["hvplot", "geoviews", "cartopy", "holoviews"],
     "overlays": ["pycoast", "pydecorate"],
     "satpos_from_tle": ["skyfield", "astropy"],
     "tests": test_requires,