Fix no init/valid time support (#1201)

* Fix no init/valid time support

Fix #1200

* adapted docstrings

Author: joernu76

mslib/mswms/mss_2D_sections.py

@@ -135,23 +135,17 @@ def uses_elevation_dimension(self):
 
     def uses_inittime_dimension(self):
         """
-        Returns whether this layer uses the WMS inittime dimension. If False,
+        Returns whether this layer uses the inittime dimension. If False,
         init_time does not have to be specified to plot_hsection().
-
-        Currently redirected to check for valid_time.
         """
-        return self.driver.uses_validtime_dimension() if self.driver is not None else False
+        return self.driver.uses_inittime_dimension() if self.driver is not None else False
 
     def uses_validtime_dimension(self):
         """
-        Returns whether this layer uses the WMS time dimension. If False,
-        valid_time does not have to be specified to
-        plot_hsection().
-
-        Currently implemented by testing whether the style requires data fields
-        from the ECMWF forecast.
+        Returns whether this layer uses the WMS (valid) time dimension. If False,
+        valid_time does not have to be specified to plot_hsection().
         """
-        return self.driver.uses_inittime_dimension() if self.driver is not None else False
+        return self.driver.uses_validtime_dimension() if self.driver is not None else False
 
     def get_elevations(self):
         """

mslib/mswms/mss_plot_driver.py

@@ -102,16 +102,15 @@ def _set_time(self, init_time, fc_time):
             self.vert_units = None
             return
 
-        if fc_time < init_time:
-            msg = "Forecast valid time cannot be earlier than " \
-                  "initialisation time."
-            logging.error(msg)
-            raise ValueError(msg)
-        fc_step = fc_time - init_time
-        fc_step = fc_step.days * 24 + (fc_step.seconds // 3600)
+        if self.uses_inittime_dimension():
+            logging.debug("\trequested initialisation time %s", init_time)
+            if fc_time < init_time:
+                msg = "Forecast valid time cannot be earlier than " \
+                      "initialisation time."
+                logging.error(msg)
+                raise ValueError(msg)
         self.fc_time = fc_time
-        logging.debug("\trequested initialisation time %s", init_time)
-        logging.debug("\trequested forecast valid time %s (step %s hrs)", fc_time, fc_step)
+        logging.debug("\trequested forecast valid time %s", fc_time)
 
         # Check if a dataset is open and if it contains the requested times.
         # (a dataset will only be open if the used layer has not changed,