correction multiple bug for tracking and zarr loading

- correction of bug in zarr nb_obs & track_array_variables, if no vars with 2 dimensions was selected
- bug when loading EddiesObservation, rotation_type was not loaded
- bug in tracking, previous_virtual_obs was not loaded from VirtualEddiesObservations

src/py_eddy_tracker/observations/observation.py

@@ -767,9 +767,8 @@ def load_from_zarr(
             h_zarr = zarr.open(filename)
         var_list = cls.build_var_list(list(h_zarr.keys()), remove_vars, include_vars)
 
-        # FIXME must be investigated, in zarr no dimensions name (or could be add in attr)
-        #   so we assume first dimension is number of observation, second is number of contours
-        nb_obs, track_array_variables = getattr(h_zarr, var_list[0]).shape
+        nb_obs = getattr(h_zarr, var_list[0]).shape[0]
+        track_array_variables = h_zarr.attrs["track_array_variables"]
 
         if indexs is not None and "obs" in indexs:
             sl = indexs["obs"]
@@ -1040,6 +1039,7 @@ def from_zarr(cls, handler):
                 eddies.obs[variable] = handler.variables[variable][:]
             else:
                 eddies.obs[VAR_DESCR_inv[variable]] = handler.variables[variable][:]
+        eddies.sign_type = handler.rotation_type
         return eddies
 
     @classmethod
@@ -1058,6 +1058,7 @@ def from_netcdf(cls, handler):
                 eddies.obs[variable] = handler.variables[variable][:]
             else:
                 eddies.obs[VAR_DESCR_inv[variable]] = handler.variables[variable][:]
+        eddies.sign_type = handler.rotation_type
         return eddies
 
     def propagate(

src/py_eddy_tracker/tracking.py

@@ -350,6 +350,9 @@ def load_state(self):
                     self.virtual_obs = VirtualEddiesObservations.from_netcdf(
                         general_handler.groups["LastVirtualObs"]
                     )
+                    self.previous_virtual_obs = VirtualEddiesObservations.from_netcdf(
+                        general_handler.groups["LastPreviousVirtualObs"]
+                    )
                     # Load and last previous virtual obs to be merge with current => will be previous2_obs
                     # TODO : Need to rethink this line ??
                     self.current_obs = self.current_obs.merge(