feat: support dimensions without coordinate variables

Dimensions that lack coordinate variables (e.g., ext_cnt,
num_gas_aerosol_constituents) now appear in the slice selection
UI with index-based sliders. Labels show the actual units when
a coordinate variable exists, or "Index value:" otherwise.

Author: berkgeveci

src/e3sm_quickview/app.py

@@ -442,20 +442,26 @@ async def data_loading_open(self, simulation, connectivity):
                 # Update Layer/Time values and ui layout
                 n_cols = 0
                 available_tracks = []
+                dim_units = {}
                 for name, dim in self.source.dimensions.items():
                     values = dim.data
                     # Convert to list for JSON serialization
-                    self.state[name] = (
-                        values.tolist()
-                        if hasattr(values, "tolist")
-                        else list(values)
-                        if values is not None
-                        else []
-                    )
+                    if values is not None:
+                        self.state[name] = (
+                            values.tolist()
+                            if hasattr(values, "tolist")
+                            else list(values)
+                        )
+                    else:
+                        self.state[name] = list(range(dim.size))
 
-                    if values is not None and len(values) > 1:
+                    if dim.size > 1:
                         n_cols += 1
                         available_tracks.append(name)
+                        if dim.units:
+                            dim_units[name] = dim.units
+
+                self.state.dim_units = dim_units
                 self.state.toolbar_slider_cols = 12 / n_cols if n_cols else 12
                 self.state.animation_tracks = available_tracks
                 self.state.animation_track = (

src/e3sm_quickview/components/toolbars.py

@@ -366,7 +366,7 @@ def __init__(self):
                                 )
                                 v3.VSpacer()
                                 v3.VLabel(
-                                    "{{ t_values ? parseFloat(t_values[t_idx]).toFixed(2) : '' }} hPa (k={{ t_idx }})",
+                                    "{{ dim_units[track] ? parseFloat(t_values[t_idx]).toFixed(2) + ' ' + dim_units[track] : 'Index value: ' + t_idx }} (k={{ t_idx }})",
                                     classes="text-body-2",
                                 )
                             v3.VSlider(
@@ -418,7 +418,7 @@ def __init__(self):
                                     classes="text-subtitle-2 ml-2 mt-1",
                                 )
                                 v3.VLabel(
-                                    "{{ t_values ? parseFloat(t_values[Number(t_idx)]).toFixed(2) : '' }} hPa",
+                                    "{{ dim_units[track] ? parseFloat(t_values[Number(t_idx)]).toFixed(2) + ' ' + dim_units[track] : 'Index value: ' + t_idx }}",
                                     classes="text-body-2 text-no-wrap ml-2 mt-1",
                                 )