psyplot · Chilipp · Apr 20, 2020 · Apr 20, 2020
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
@@ -6,7 +6,9 @@ Added
   different input types for the decoder. You can pass an instance of the
   ``CFDecoder`` class, a sub class of ``CFDecoder``, or keyword arguments
   that are used to initialize the decoder,
-  see `#20 <https://github.com/psyplot/psyplot/pull/20>`__
+  see `#20 <https://github.com/psyplot/psyplot/pull/20>`__. Furthermore, the
+  `check_data` method of the various plotmethods now also accept a `decoder`
+  parameter, see `#22 <https://github.com/psyplot/psyplot/pull/22>`__
 * `psyplot.data.open_dataset` now decodes grid_mappings attributes,
 see `#17 <https://github.com/psyplot/psyplot/pull/17>`__
 * psyplot projects now support the with syntax, e.g. something like::

diff --git a/psyplot/project.py b/psyplot/project.py
@@ -1857,7 +1857,7 @@ def docs(self, *args, **kwargs):
         return self.plotter_cls.show_docs(*args, **kwargs)
 
     @docstrings.dedent
-    def check_data(self, ds, name, dims):
+    def check_data(self, ds, name, dims, decoder=None, *args, **kwargs):
         """
         A validation method for the data shape
 
@@ -1872,6 +1872,10 @@ def check_data(self, ds, name, dims):
             dimensions of this plot method
         is_unstructured: bool or list of bool
             True if the corresponding array is unstructured.
+        decoder: :class:`psyplot.data.CFDecoder`, dict or a list of them
+            The decoders to use per array. Dictionaries are parsed as keyword
+            arguments to the :meth:`psyplot.data.CFDecoder.get_decoder`
+            method
 
         Returns
         -------
@@ -1880,10 +1884,19 @@ def check_data(self, ds, name, dims):
         if isinstance(name, six.string_types):
             name = [name]
             dims = [dims]
+            decoders = [decoder]
         else:
             dims = list(dims)
+            decoders = list(decoder if decoder is not None else [None])
         variables = [ds[safe_list(n)[0]] for n in name]
-        decoders = [CFDecoder.get_decoder(ds, var) for var in variables]
+        if decoders is None:
+            decoders = [CFDecoder.get_decoder(ds, var) for var in variables]
+        else:
+            for i, (decoder, var) in enumerate(zip(decoders, variables)):
+                if decoder is None:
+                    decoder = {}
+                if isinstance(decoder, dict):
+                    decoders[i] = CFDecoder.get_decoder(ds, var, **decoder)
         default_slice = slice(None) if self._default_slice is None else \
             self._default_slice
         for i, (dim_dict, var, decoder) in enumerate(zip(

diff --git a/tests/test_project.py b/tests/test_project.py
@@ -1492,10 +1492,17 @@ def check_data(cls, name, dims, is_unstructured):
                 checks, messages = super(TestPlotter, cls).check_data(
                     name, dims, is_unstructured)
                 self.assertEqual(name, ['t2m'])
+
                 for n, d in zip(name, dims):
+                    if test_x:  # changed x-coordinate
+                        removed = {'lev', 'time'}
+                    else:
+                        removed = {'lev', 'lon'}
                     self.assertEqual(len(d),
-                                     len(set(ds.t2m.dims) - {'lev', 'lon'}))
-                    self.assertEqual(set(d), set(ds.t2m.dims) - {'lev', 'lon'})
+                                     len(set(ds.t2m.dims) - removed))
+                    self.assertEqual(set(d), set(ds.t2m.dims) - removed)
+
+        test_x = False
 
         ds = psy.open_dataset(bt.get_file('test-t2m-u-v.nc'))
 
@@ -1504,6 +1511,11 @@ def check_data(cls, name, dims, is_unstructured):
                              default_dims={'x': 1}, default_slice=slice(1, 3))
 
         psy.plot.test_plotter.check_data(ds, 't2m', {'lev': 3})
+
+        test_x = True
+        psy.plot.test_plotter.check_data(ds, 't2m', {'lev': 3},
+                                         {'x': {'time'}})
+
         psy.unregister_plotter('test_plotter')