diff --git a/src/earthkit/data/field/component/geography.py b/src/earthkit/data/field/component/geography.py
index 0a71eed15..cf6aa1079 100644
--- a/src/earthkit/data/field/component/geography.py
+++ b/src/earthkit/data/field/component/geography.py
@@ -488,12 +488,8 @@ def set(self, *args, shape_hint=None, **kwargs) -> "GeographyBase":
         kwargs = self._normalise_set_kwargs(*args, **kwargs)
         keys = set(kwargs.keys())
 
-        if keys == {"grid_spec"}:
-            spec = self.from_grid_spec(self, kwargs["grid_spec"])
-            return spec
-        if keys == {"latitudes", "longitudes"}:
-            spec = self.from_dict(kwargs, shape_hint=shape_hint)
-            return spec
+        if keys == {"grid_spec"} or keys == {"latitudes", "longitudes"}:
+            return self.from_dict(kwargs, shape_hint=shape_hint)
 
         raise ValueError(f"Invalid {keys=} for Geography specification")
 
diff --git a/src/earthkit/data/field/geotiff/geography.py b/src/earthkit/data/field/geotiff/geography.py
index 4451f5a46..33e608a14 100644
--- a/src/earthkit/data/field/geotiff/geography.py
+++ b/src/earthkit/data/field/geotiff/geography.py
@@ -86,9 +86,9 @@ def grid(self):
     def area(self):
         pass
 
-    @classmethod
-    def from_dict(d):
-        raise NotImplementedError("XArrayGeography.form_dict() is not implemented")
+    # @classmethod
+    # def from_dict(d):
+    #     raise NotImplementedError("XArrayGeography.form_dict() is not implemented")
 
     def _grid_mapping(self):
         if self._ds.rio.grid_mapping == "spatial_ref":
diff --git a/src/earthkit/data/field/grib/geography.py b/src/earthkit/data/field/grib/geography.py
index 196886438..20528c313 100644
--- a/src/earthkit/data/field/grib/geography.py
+++ b/src/earthkit/data/field/grib/geography.py
@@ -170,9 +170,9 @@ def grid_type(self):
         r"""Return the grid type."""
         return self.handle.get("gridType", default=None)
 
-    @classmethod
-    def from_dict(*args, **kwargs):
-        raise NotImplementedError("GribGeography cannot be created from a dictionary")
+    # @classmethod
+    # def from_dict(*args, **kwargs):
+    #     raise NotImplementedError("GribGeography cannot be created from a dictionary")
 
     # def to_dict(self):
     #     return dict()
diff --git a/src/earthkit/data/field/handler/core.py b/src/earthkit/data/field/handler/core.py
index 1c51a8bb0..e5a584ff8 100644
--- a/src/earthkit/data/field/handler/core.py
+++ b/src/earthkit/data/field/handler/core.py
@@ -217,12 +217,14 @@ def __init__(self, component: Any) -> None:
     def from_dict(cls, d: dict, **kwargs) -> "SimpleFieldComponentHandler":
         """Create a SimpleFieldComponent object from a dictionary."""
         component = cls.COMPONENT_MAKER(d, **kwargs)
-        return cls(component)
+        return cls.from_component(component)
 
     @classmethod
+    @abstractmethod
     def from_component(cls, component: Any) -> "SimpleFieldComponentHandler":
         """Create a SimpleFieldComponent object from a component object."""
-        return cls(component)
+        # return cls._from_component(component)
+        pass
 
     @classmethod
     def from_any(cls, data: Any, dict_kwargs=None) -> "SimpleFieldComponentHandler":
diff --git a/src/earthkit/data/field/handler/ensemble.py b/src/earthkit/data/field/handler/ensemble.py
index 76c3c628d..cdbc6b845 100644
--- a/src/earthkit/data/field/handler/ensemble.py
+++ b/src/earthkit/data/field/handler/ensemble.py
@@ -24,6 +24,10 @@ def get_grib_context(self, context) -> dict:
 
         COLLECTOR.collect(self, context)
 
+    @classmethod
+    def from_component(cls, component: EnsembleBase) -> "EnsembleFieldComponentHandler":
+        return EnsembleFieldComponentHandler(component)
+
     @classmethod
     def create_empty(cls) -> "EnsembleFieldComponentHandler":
         return EMPTY_ENSEMBLE_HANDLER
diff --git a/src/earthkit/data/field/handler/geography.py b/src/earthkit/data/field/handler/geography.py
index 8deb789e3..f079244a3 100644
--- a/src/earthkit/data/field/handler/geography.py
+++ b/src/earthkit/data/field/handler/geography.py
@@ -24,6 +24,10 @@ def get_grib_context(self, context) -> dict:
 
         COLLECTOR.collect(self, context)
 
+    @classmethod
+    def from_component(cls, component: GeographyBase) -> "GeographyFieldComponentHandler":
+        return GeographyFieldComponentHandler(component)
+
     @classmethod
     def create_empty(cls) -> "GeographyFieldComponentHandler":
         return EMPTY_GEOGRAPHY_HANDLER
diff --git a/src/earthkit/data/field/handler/parameter.py b/src/earthkit/data/field/handler/parameter.py
index e8b652f8d..a315b8eb8 100644
--- a/src/earthkit/data/field/handler/parameter.py
+++ b/src/earthkit/data/field/handler/parameter.py
@@ -24,6 +24,10 @@ def get_grib_context(self, context) -> dict:
 
         COLLECTOR.collect(self, context)
 
+    @classmethod
+    def from_component(cls, component: ParameterBase) -> "ParameterFieldComponentHandler":
+        return ParameterFieldComponentHandler(component)
+
     @classmethod
     def create_empty(cls) -> "ParameterFieldComponentHandler":
         return EMPTY_PARAMETER_HANDLER
diff --git a/src/earthkit/data/field/handler/proc.py b/src/earthkit/data/field/handler/proc.py
index 51d317e1c..506611a8e 100644
--- a/src/earthkit/data/field/handler/proc.py
+++ b/src/earthkit/data/field/handler/proc.py
@@ -27,6 +27,10 @@ def set(self, *args, **kwargs):
         spec = self._spec.set(*args, **kwargs)
         return ProcFieldComponentHandler(spec)
 
+    @classmethod
+    def from_component(cls, component: ProcBase) -> "ProcFieldComponentHandler":
+        return ProcFieldComponentHandler(component)
+
     @classmethod
     def create_empty(cls) -> "ProcFieldComponentHandler":
         return EMPTY_PROC_HANDLER
diff --git a/src/earthkit/data/field/handler/time.py b/src/earthkit/data/field/handler/time.py
index e86c3fc15..097478c30 100644
--- a/src/earthkit/data/field/handler/time.py
+++ b/src/earthkit/data/field/handler/time.py
@@ -25,6 +25,10 @@ def get_grib_context(self, context) -> dict:
 
         COLLECTOR.collect(self, context)
 
+    @classmethod
+    def from_component(cls, component: TimeBase) -> "TimeFieldComponentHandler":
+        return TimeFieldComponentHandler(component)
+
     @classmethod
     def create_empty(cls) -> "TimeFieldComponentHandler":
         return EMPTY_TIME_HANDLER
diff --git a/src/earthkit/data/field/handler/vertical.py b/src/earthkit/data/field/handler/vertical.py
index 417397f85..aba8b185c 100644
--- a/src/earthkit/data/field/handler/vertical.py
+++ b/src/earthkit/data/field/handler/vertical.py
@@ -24,6 +24,10 @@ def get_grib_context(self, context) -> dict:
 
         COLLECTOR.collect(self, context)
 
+    @classmethod
+    def from_component(cls, component: VerticalBase) -> "VerticalFieldComponentHandler":
+        return VerticalFieldComponentHandler(component)
+
     @classmethod
     def create_empty(cls) -> "VerticalFieldComponentHandler":
         return EMPTY_VERTICAL_HANDLER
diff --git a/src/earthkit/data/field/xarray/geography.py b/src/earthkit/data/field/xarray/geography.py
index dd87629bf..db1919156 100644
--- a/src/earthkit/data/field/xarray/geography.py
+++ b/src/earthkit/data/field/xarray/geography.py
@@ -81,9 +81,9 @@ def grid(self):
         r"""Return the area of the grid."""
         pass
 
-    @classmethod
-    def from_dict(d):
-        raise NotImplementedError("XArrayGeography.form_dict() is not implemented")
+    # @classmethod
+    # def from_dict(*args, **kwargs):
+    #     raise NotImplementedError("XArrayGeography cannot be created from a dictionary")
 
     def latlons(self, flatten=False, dtype=None):
         lat, lon = self.owner.grid.latlons
diff --git a/tests/grib/test_grib_set_data.py b/tests/grib/test_grib_set_data.py
index dca494858..c349c6913 100644
--- a/tests/grib/test_grib_set_data.py
+++ b/tests/grib/test_grib_set_data.py
@@ -20,7 +20,7 @@
 
 # @pytest.mark.parametrize("fl_type", ["file", "array", "memory"])
 @pytest.mark.parametrize("fl_type", ["file"])
-def test_grib_set_data(fl_type):
+def test_grib_set_data_field(fl_type):
     ds_ori, _ = load_grib_data("test4.grib", fl_type)
 
     vals_ori = ds_ori[0].values
@@ -76,9 +76,12 @@ def test_grib_set_data(fl_type):
     # assert grib_md.get("levelist") == 500
     # assert grib_md.get("date") == 20070101
 
-    # ---------------
-    # fieldlist
-    # ---------------
+
+@pytest.mark.parametrize("fl_type", ["file"])
+def test_grib_set_data_fieldlist(fl_type):
+    ds_ori, _ = load_grib_data("test4.grib", fl_type)
+
+    vals_ori = ds_ori[0].values
 
     fields = []
     for i in range(2):
diff --git a/tests/grib/test_grib_set_time.py b/tests/grib/test_grib_set_time.py
index afcdc9238..b2ce8ba18 100644
--- a/tests/grib/test_grib_set_time.py
+++ b/tests/grib/test_grib_set_time.py
@@ -20,7 +20,6 @@
 
 # @pytest.mark.parametrize("fl_type", ["file", "array", "memory"])
 @pytest.mark.parametrize("fl_type", ["file"])
-@pytest.mark.parametrize("write_method", ["target"])
 @pytest.mark.parametrize(
     "_kwargs,ref_set,ref_saved,edition_saved",
     [
@@ -336,7 +335,7 @@
         # ),
     ],
 )
-def test_grib_set_time_1(fl_type, write_method, _kwargs, ref_set, ref_saved, edition_saved):
+def test_grib_set_time_1(fl_type, _kwargs, ref_set, ref_saved, edition_saved):
     ds_ori, _ = load_grib_data("test4.grib", fl_type)
 
     f = ds_ori[0].set(**_kwargs)
diff --git a/tests/grib/test_grib_set_vertical.py b/tests/grib/test_grib_set_vertical.py
index c7a2a3e80..e49aa2d18 100644
--- a/tests/grib/test_grib_set_vertical.py
+++ b/tests/grib/test_grib_set_vertical.py
@@ -19,7 +19,6 @@
 
 # @pytest.mark.parametrize("fl_type", ["file", "array", "memory"])
 @pytest.mark.parametrize("fl_type", ["file"])
-@pytest.mark.parametrize("write_method", ["target"])
 @pytest.mark.parametrize(
     "_kwargs,ref1,grib_ref,ref2",
     [
@@ -79,7 +78,7 @@
         # ),
     ],
 )
-def test_grib_set_vertical(fl_type, write_method, _kwargs, ref1, grib_ref, ref2):
+def test_grib_set_vertical(fl_type, _kwargs, ref1, grib_ref, ref2):
     ds_ori, _ = load_grib_data("test4.grib", fl_type)
 
     f = ds_ori[0].set(**_kwargs)
diff --git a/tests/list_of_dicts/test_lod_set_data.py b/tests/list_of_dicts/test_lod_set_data.py
new file mode 100644
index 000000000..fdcc99b5d
--- /dev/null
+++ b/tests/list_of_dicts/test_lod_set_data.py
@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+
+# (C) Copyright 2020 ECMWF.
+#
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+#
+
+
+import numpy as np
+import pytest
+from lod_fixtures import build_lod_fieldlist  # noqa: E402
+
+from earthkit.data import FieldList
+
+
+@pytest.mark.parametrize("mode", ["list-of-dicts", "loop"])
+def test_lod_set_data_field(lod_ll_flat, mode):
+    ds_ori = build_lod_fieldlist(lod_ll_flat, mode)
+
+    vals_ori = ds_ori[0].values
+
+    f = ds_ori[0].set(values=vals_ori + 1)
+
+    assert f.get("parameter.variable") == "t"
+    assert f.get("vertical.level") == 500
+    assert np.allclose(f.values, vals_ori + 1)
+    assert np.allclose(ds_ori[0].values, vals_ori)
+
+    # ---------------------
+    # field - repeated use
+    # ---------------------
+
+    f = ds_ori[0].set(values=vals_ori + 1)
+    f = f.set(values=vals_ori + 2)
+
+    assert f.get("parameter.variable") == "t"
+    assert f.get("vertical.level") == 500
+    assert np.allclose(f.values, vals_ori + 2)
+    assert np.allclose(ds_ori[0].values, vals_ori)
+
+
+@pytest.mark.parametrize("mode", ["list-of-dicts", "loop"])
+def test_lod_set_data_fieldlist(lod_ll_flat, mode):
+    ds_ori = build_lod_fieldlist(lod_ll_flat, mode)
+
+    vals_ori = ds_ori[0].values
+
+    fields = []
+    for i in range(2):
+        f = ds_ori[i].set(values=vals_ori + i + 1)
+        fields.append(f)
+
+    ds = FieldList.from_fields(fields)
+
+    assert ds.get("parameter.variable") == ["t", "t"]
+    assert ds.get("vertical.level") == [500, 850]
+    assert np.allclose(ds[0].values, vals_ori + 1)
+    assert np.allclose(ds[1].values, vals_ori + 2)
diff --git a/tests/list_of_dicts/test_lod_set_geography.py b/tests/list_of_dicts/test_lod_set_geography.py
new file mode 100644
index 000000000..adb245e45
--- /dev/null
+++ b/tests/list_of_dicts/test_lod_set_geography.py
@@ -0,0 +1,81 @@
+#!/usr/bin/env python3
+
+# (C) Copyright 2020 ECMWF.
+#
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+#
+
+import datetime
+
+import numpy as np
+import pytest
+from lod_fixtures import build_lod_fieldlist  # noqa: E402
+
+
+@pytest.mark.parametrize("mode", ["list-of-dicts", "loop"])
+@pytest.mark.parametrize(
+    "_kwargs",
+    [
+        {
+            "geography.latitudes": np.array([10.0, 20.0, 30.0]),
+            "geography.longitudes": np.array([0.0, 10.0, 20.0]),
+            "values": np.array([1.0, 2.0, 3.0]),
+        },
+    ],
+)
+def test_lod_set_geo_1(lod_ll_flat, mode, _kwargs):
+    ds_ori = build_lod_fieldlist(lod_ll_flat, mode)
+
+    f = ds_ori[0].set(**_kwargs)
+    assert np.allclose(f.get("geography.latitudes"), np.array([10.0, 20.0, 30.0]))
+    assert np.allclose(f.get("geography.longitudes"), np.array([0.0, 10.0, 20.0]))
+    assert np.allclose(f.values, np.array([1.0, 2.0, 3.0]))
+    assert f.get("time.base_datetime") == datetime.datetime(2018, 8, 1, 9, 0)
+    assert f.get("time.valid_datetime") == datetime.datetime(2018, 8, 1, 9, 0)
+    assert f.get("time.step") == datetime.timedelta(hours=0)
+    # assert f.get("time_span") == datetime.timedelta(hours=0)
+
+    # the original field is unchanged
+    assert ds_ori[0].get("geography.latitudes").shape == (6,)
+    assert ds_ori[0].get("geography.longitudes").shape == (6,)
+    assert ds_ori[0].values.shape == (6,)
+    assert ds_ori[0].get("time.base_datetime") == datetime.datetime(2018, 8, 1, 9, 0)
+    assert ds_ori[0].get("time.valid_datetime") == datetime.datetime(2018, 8, 1, 9, 0)
+    assert ds_ori[0].get("time.step") == datetime.timedelta(hours=0)
+    # assert ds_ori[0].get("time_span") == datetime.timedelta(hours=0)
+
+
+@pytest.mark.parametrize("mode", ["list-of-dicts", "loop"])
+@pytest.mark.parametrize(
+    "_kwargs,shape,grid_spec,area_1",
+    [
+        (
+            {
+                "geography.grid_spec": {"grid": [5, 5]},
+                "values": np.ones((37, 72)),
+            },
+            (37, 72),
+            {"grid": [5, 5]},
+            (90, 0, -90, 360),
+        ),
+    ],
+)
+def test_lod_set_geo_grid_spec(lod_ll_flat, mode, _kwargs, shape, grid_spec, area_1):
+    # the input is a 1/1 grid
+    ds_ori = build_lod_fieldlist(lod_ll_flat, mode)
+
+    assert ds_ori[0].shape == (6,)
+
+    f = ds_ori[0].set(**_kwargs)
+    assert f.shape == shape
+    assert f.get("geography.shape") == shape
+    assert f.get("geography.area") == area_1
+    assert f.get("geography.grid_spec") == grid_spec
+    # assert f.get("geography.grid_type") == grid_type
+    assert f.get("geography.latitudes").shape == shape
+    assert f.get("geography.longitudes").shape == shape
+    assert np.allclose(f.to_numpy(), _kwargs["values"])
diff --git a/tests/list_of_dicts/test_lod_set_vertical.py b/tests/list_of_dicts/test_lod_set_vertical.py
new file mode 100644
index 000000000..7c0688ce9
--- /dev/null
+++ b/tests/list_of_dicts/test_lod_set_vertical.py
@@ -0,0 +1,44 @@
+#!/usr/bin/env python3
+
+# (C) Copyright 2020 ECMWF.
+#
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+#
+
+import pytest
+from lod_fixtures import build_lod_fieldlist  # noqa: E402
+
+
+@pytest.mark.parametrize("mode", ["list-of-dicts", "loop"])
+@pytest.mark.parametrize(
+    "_kwargs,ref",
+    [
+        (
+            {
+                "vertical.level": 320,
+                "vertical.level_type": "potential_temperature",
+            },
+            {
+                "vertical.level": 320,
+                "vertical.level_type": "potential_temperature",
+                "vertical.units": "K",
+                "vertical.abbreviation": "pt",
+            },
+        ),
+    ],
+)
+def test_lod_set_vertical(lod_ll_flat, mode, _kwargs, ref):
+    ds = build_lod_fieldlist(lod_ll_flat, mode)
+
+    f = ds[0].set(**_kwargs)
+
+    for k, v in ref.items():
+        assert f.get(k) == v
+
+    # the original field is unchanged
+    assert ds[0].get("vertical.level") == 500
+    assert ds[0].get("vertical.level_type") == "unknown"
diff --git a/tests/netcdf/test_netcdf_set_data.py b/tests/netcdf/test_netcdf_set_data.py
new file mode 100644
index 000000000..a0826f73f
--- /dev/null
+++ b/tests/netcdf/test_netcdf_set_data.py
@@ -0,0 +1,66 @@
+#!/usr/bin/env python3
+
+# (C) Copyright 2020 ECMWF.
+#
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+#
+
+
+import numpy as np
+import pytest
+
+from earthkit.data import FieldList
+from earthkit.data.utils.testing import earthkit_test_data_file, load_nc_or_xr_source
+
+
+@pytest.mark.parametrize("mode", ["nc", "xr"])
+def test_netcdf_set_data_field(mode):
+    ds_ori = load_nc_or_xr_source(earthkit_test_data_file("test4.nc"), mode)
+
+    vals_ori = ds_ori[0].values
+
+    f = ds_ori[0].set(values=vals_ori + 1)
+
+    assert f.get("parameter.variable") == "t"
+    assert f.get("vertical.level") == 500
+    assert f.get(("metadata.date", "parameter.variable")) == (None, "t")
+    assert f.get(("parameter.variable", "metadata.date")) == ("t", None)
+    assert np.allclose(f.values, vals_ori + 1)
+    assert np.allclose(ds_ori[0].values, vals_ori)
+
+    # ---------------------
+    # field - repeated use
+    # ---------------------
+
+    f = ds_ori[0].set(values=vals_ori + 1)
+    f = f.set(values=vals_ori + 2)
+
+    assert f.get("parameter.variable") == "t"
+    assert f.get("vertical.level") == 500
+    assert f.get(("metadata.date", "parameter.variable")) == (None, "t")
+    assert f.get(("parameter.variable", "metadata.date")) == ("t", None)
+    assert np.allclose(f.values, vals_ori + 2)
+    assert np.allclose(ds_ori[0].values, vals_ori)
+
+
+@pytest.mark.parametrize("mode", ["nc", "xr"])
+def test_netcdf_set_data_fieldlist(mode):
+    ds_ori = load_nc_or_xr_source(earthkit_test_data_file("test4.nc"), mode)
+
+    vals_ori = ds_ori[0].values
+
+    fields = []
+    for i in range(2):
+        f = ds_ori[i].set(values=vals_ori + i + 1)
+        fields.append(f)
+
+    ds = FieldList.from_fields(fields)
+
+    assert ds.get("parameter.variable") == ["t", "t"]
+    assert ds.get("vertical.level") == [500, 850]
+    assert np.allclose(ds[0].values, vals_ori + 1)
+    assert np.allclose(ds[1].values, vals_ori + 2)
diff --git a/tests/netcdf/test_netcdf_set_geography.py b/tests/netcdf/test_netcdf_set_geography.py
new file mode 100644
index 000000000..7f5a599bc
--- /dev/null
+++ b/tests/netcdf/test_netcdf_set_geography.py
@@ -0,0 +1,82 @@
+#!/usr/bin/env python3
+
+# (C) Copyright 2020 ECMWF.
+#
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+#
+
+import datetime
+
+import numpy as np
+import pytest
+
+from earthkit.data.utils.testing import earthkit_test_data_file, load_nc_or_xr_source
+
+
+@pytest.mark.parametrize("mode", ["nc", "xr"])
+@pytest.mark.parametrize(
+    "_kwargs",
+    [
+        {
+            "geography.latitudes": np.array([10.0, 20.0, 30.0]),
+            "geography.longitudes": np.array([0.0, 10.0, 20.0]),
+            "values": np.array([1.0, 2.0, 3.0]),
+        },
+    ],
+)
+def test_netcdf_set_geo_1(mode, _kwargs):
+    ds_ori = load_nc_or_xr_source(earthkit_test_data_file("test4.nc"), mode)
+
+    f = ds_ori[0].set(**_kwargs)
+    assert np.allclose(f.get("geography.latitudes"), np.array([10.0, 20.0, 30.0]))
+    assert np.allclose(f.get("geography.longitudes"), np.array([0.0, 10.0, 20.0]))
+    assert np.allclose(f.values, np.array([1.0, 2.0, 3.0]))
+    assert f.get("time.base_datetime") == datetime.datetime(2007, 1, 1, 12)
+    assert f.get("time.valid_datetime") == datetime.datetime(2007, 1, 1, 12)
+    assert f.get("time.step") == datetime.timedelta(hours=0)
+    # assert f.get("time_span") == datetime.timedelta(hours=0)
+
+    # the original field is unchanged
+    assert ds_ori[0].get("geography.latitudes").shape == (181, 360)
+    assert ds_ori[0].get("geography.longitudes").shape == (181, 360)
+    assert ds_ori[0].values.shape == (65160,)
+    assert ds_ori[0].get("time.base_datetime") == datetime.datetime(2007, 1, 1, 12)
+    assert ds_ori[0].get("time.valid_datetime") == datetime.datetime(2007, 1, 1, 12)
+    assert ds_ori[0].get("time.step") == datetime.timedelta(hours=0)
+    # assert ds_ori[0].get("time_span") == datetime.timedelta(hours=0)
+
+
+@pytest.mark.parametrize("mode", ["nc", "xr"])
+@pytest.mark.parametrize(
+    "_kwargs,shape,grid_spec,area_1",
+    [
+        (
+            {
+                "geography.grid_spec": {"grid": [5, 5]},
+                "values": np.ones((37, 72)),
+            },
+            (37, 72),
+            {"grid": [5, 5]},
+            (90, 0, -90, 360),
+        ),
+    ],
+)
+def test_netcdf_set_geo_grid_spec(mode, _kwargs, shape, grid_spec, area_1):
+    # the input is a 1/1 grid
+    ds_ori = load_nc_or_xr_source(earthkit_test_data_file("test4.nc"), mode)
+
+    assert ds_ori[0].shape == (181, 360)
+
+    f = ds_ori[0].set(**_kwargs)
+    assert f.shape == shape
+    assert f.get("geography.shape") == shape
+    assert f.get("geography.area") == area_1
+    assert f.get("geography.grid_spec") == grid_spec
+    # assert f.get("geography.grid_type") == grid_type
+    assert f.get("geography.latitudes").shape == shape
+    assert f.get("geography.longitudes").shape == shape
+    assert np.allclose(f.to_numpy(), _kwargs["values"])
diff --git a/tests/netcdf/test_netcdf_set_parameter.py b/tests/netcdf/test_netcdf_set_parameter.py
new file mode 100644
index 000000000..41382b3f9
--- /dev/null
+++ b/tests/netcdf/test_netcdf_set_parameter.py
@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+
+# (C) Copyright 2020 ECMWF.
+#
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+#
+
+
+import pytest
+
+from earthkit.data.utils.testing import earthkit_examples_file, earthkit_test_data_file, load_nc_or_xr_source
+
+
+@pytest.mark.parametrize("mode", ["nc", "xr"])
+def test_netcdf_set_parameter_1(mode):
+    ds = load_nc_or_xr_source(earthkit_test_data_file("test_single.nc"), mode)
+    f = ds[0]
+
+    assert f.parameter.variable() == "t2m"
+    assert f.parameter.standard_name() == "unknown"
+    assert f.parameter.long_name() == "2 metre temperature"
+    assert f.parameter.param() == "t2m"
+    assert f.parameter.units() == "K"
+
+
+@pytest.mark.parametrize("mode", ["nc", "xr"])
+def test_netcdf_set_parameter_2(mode):
+    ds = load_nc_or_xr_source(earthkit_examples_file("tuv_pl.grib"), mode)
+    f = ds[0]
+
+    assert f.parameter.variable() == "t"
+    assert f.parameter.standard_name() == "air_temperature"
+    assert f.parameter.long_name() == "Temperature"
+    assert f.parameter.param() == "t"
+    assert f.parameter.units() == "K"
diff --git a/tests/netcdf/test_netcdf_set_time.py b/tests/netcdf/test_netcdf_set_time.py
new file mode 100644
index 000000000..7f3332a90
--- /dev/null
+++ b/tests/netcdf/test_netcdf_set_time.py
@@ -0,0 +1,178 @@
+#!/usr/bin/env python3
+
+# (C) Copyright 2020 ECMWF.
+#
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+#
+
+import datetime
+
+import pytest
+
+from earthkit.data.utils.testing import earthkit_test_data_file, load_nc_or_xr_source
+
+
+@pytest.mark.parametrize("mode", ["nc", "xr"])
+@pytest.mark.parametrize(
+    "_kwargs,ref_set",
+    [
+        (
+            {"time.base_datetime": "2025-08-24T12:00:00", "time.step": 6},
+            {
+                "time.base_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.valid_datetime": datetime.datetime(2025, 8, 24, 18),
+                "time.step": datetime.timedelta(hours=6),
+                # "time_span": TimeSpan(),
+            },
+        ),
+        (
+            {
+                "time.base_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.step": datetime.timedelta(hours=6),
+            },
+            {
+                "time.base_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.valid_datetime": datetime.datetime(2025, 8, 24, 18),
+                "time.step": datetime.timedelta(hours=6),
+                # "time_span": TimeSpan(),
+            },
+        ),
+        (
+            {"time.valid_datetime": "2025-08-24T18:00:00", "time.step": datetime.timedelta(hours=6)},
+            {
+                "time.base_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.valid_datetime": datetime.datetime(2025, 8, 24, 18),
+                "time.step": datetime.timedelta(hours=6),
+                # "time_span": TimeSpan(),
+            },
+        ),
+        (
+            {
+                "time.valid_datetime": datetime.datetime(2025, 8, 24, 18),
+                "time.step": datetime.timedelta(hours=6),
+            },
+            {
+                "time.base_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.valid_datetime": datetime.datetime(2025, 8, 24, 18),
+                "time.step": datetime.timedelta(hours=6),
+                # "time_span": TimeSpan(),
+            },
+        ),
+        (
+            {"time.base_datetime": "2025-08-24T12:00:00"},
+            {
+                "time.base_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.valid_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.step": datetime.timedelta(hours=0),
+                # "time_span": TimeSpan(),
+            },
+        ),
+        (
+            {"time.base_datetime": datetime.datetime(2025, 8, 24, 12)},
+            {
+                "time.base_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.valid_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.step": datetime.timedelta(hours=0),
+                # "time_span": TimeSpan(),
+            },
+        ),
+        (
+            {"time.valid_datetime": "2025-08-24T12:00:00", "time.step": 0},
+            {
+                "time.base_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.valid_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.step": datetime.timedelta(hours=0),
+                # "time_span": TimeSpan(),
+            },
+        ),
+        (
+            {
+                "time.valid_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.step": datetime.timedelta(hours=0),
+            },
+            {
+                "time.base_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.valid_datetime": datetime.datetime(2025, 8, 24, 12),
+                "time.step": datetime.timedelta(hours=0),
+                # "time_span": TimeSpan(),
+            },
+        ),
+        (
+            {"time.valid_datetime": "2007-01-03T18:00:00"},
+            {
+                "time.base_datetime": datetime.datetime(2007, 1, 1, 12),
+                "time.valid_datetime": datetime.datetime(2007, 1, 3, 18),
+                "time.step": datetime.timedelta(hours=54),
+                # "time_span": TimeSpan(),
+            },
+        ),
+        (
+            {"time.valid_datetime": datetime.datetime(2007, 1, 3, 18)},
+            {
+                "time.base_datetime": datetime.datetime(2007, 1, 1, 12),
+                "time.valid_datetime": datetime.datetime(2007, 1, 3, 18),
+                "time.step": datetime.timedelta(hours=54),
+                # "time_span": TimeSpan(),
+            },
+        ),
+        (
+            {
+                "time.valid_datetime": datetime.datetime(2007, 1, 3, 18),
+                # "time_span": TimeSpan(1, TimeSpanMethod.AVERAGE),
+            },
+            {
+                "time.base_datetime": datetime.datetime(2007, 1, 1, 12),
+                "time.valid_datetime": datetime.datetime(2007, 1, 3, 18),
+                "time.step": datetime.timedelta(hours=54),
+                # "time_span": TimeSpan(datetime.timedelta(hours=1), TimeSpanMethod.AVERAGE),
+            },
+        ),
+        (
+            {"time.step": datetime.timedelta(hours=6)},
+            {
+                "time.base_datetime": datetime.datetime(2007, 1, 1, 12),
+                "time.valid_datetime": datetime.datetime(2007, 1, 1, 18),
+                "time.step": datetime.timedelta(hours=6),
+                # "time_span": TimeSpan(),
+            },
+        ),
+        (
+            {"time.step": datetime.timedelta(hours=6, minutes=30)},
+            {
+                "time.base_datetime": datetime.datetime(2007, 1, 1, 12),
+                "time.valid_datetime": datetime.datetime(2007, 1, 1, 18, 30),
+                "time.step": datetime.timedelta(hours=6, minutes=30),
+                # "time_span": TimeSpan(),
+            },
+        ),
+        (
+            {
+                "time.step": datetime.timedelta(hours=36),
+                # "time_span": TimeSpan(datetime.timedelta(days=1), TimeSpanMethod.AVERAGE),
+            },
+            {
+                "time.base_datetime": datetime.datetime(2007, 1, 1, 12),
+                "time.valid_datetime": datetime.datetime(2007, 1, 3, 0),
+                "time.step": datetime.timedelta(hours=36),
+                # "time_span": TimeSpan(datetime.timedelta(days=1), TimeSpanMethod.AVERAGE),
+            },
+        ),
+    ],
+)
+def test_netcdf_set_time_1(mode, _kwargs, ref_set):
+    ds_ori = load_nc_or_xr_source(earthkit_test_data_file("test4.nc"), mode)
+
+    f = ds_ori[0].set(**_kwargs)
+
+    for k, v in ref_set.items():
+        assert f.get(k) == v, f"key {k} expected {v} got {f.get(k)}"
+
+    # original message is unchanged
+    assert ds_ori[0].get("time.base_datetime") == datetime.datetime(2007, 1, 1, 12)
+    assert ds_ori[0].get("time.valid_datetime") == datetime.datetime(2007, 1, 1, 12)
+    assert ds_ori[0].get("time.step") == datetime.timedelta(hours=0)
+    # assert ds_ori[0].get("time_span") == datetime.timedelta(hours=0)
diff --git a/tests/netcdf/test_netcdf_set_vertical.py b/tests/netcdf/test_netcdf_set_vertical.py
new file mode 100644
index 000000000..68fe7bda8
--- /dev/null
+++ b/tests/netcdf/test_netcdf_set_vertical.py
@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+
+# (C) Copyright 2020 ECMWF.
+#
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+#
+
+
+import pytest
+
+from earthkit.data.utils.testing import earthkit_test_data_file, load_nc_or_xr_source
+
+
+@pytest.mark.parametrize("mode", ["nc", "xr"])
+@pytest.mark.parametrize(
+    "_kwargs,ref",
+    [
+        (
+            {
+                "vertical.level": 320,
+                "vertical.level_type": "potential_temperature",
+            },
+            {
+                "vertical.level": 320,
+                "vertical.level_type": "potential_temperature",
+                "vertical.units": "K",
+                "vertical.abbreviation": "pt",
+            },
+        ),
+    ],
+)
+def test_netcdf_set_vertical(mode, _kwargs, ref):
+    ds = load_nc_or_xr_source(earthkit_test_data_file("test4.nc"), mode)
+
+    f = ds[0].set(**_kwargs)
+
+    for k, v in ref.items():
+        assert f.get(k) == v
+
+    # the original field is unchanged
+    assert ds[0].get("vertical.level") == 500
+    assert ds[0].get("vertical.level_type") == "pressure"