Index: wflow-py/wflow/wf_netcdfio.py
===================================================================
diff -u -r036ea699f3b9e9fe82ce54ea08b6fc94990408f2 -rbadbe2001f39533e20aa0d5803688e6cb6a82ea9
--- wflow-py/wflow/wf_netcdfio.py	(.../wf_netcdfio.py)	(revision 036ea699f3b9e9fe82ce54ea08b6fc94990408f2)
+++ wflow-py/wflow/wf_netcdfio.py	(.../wf_netcdfio.py)	(revision badbe2001f39533e20aa0d5803688e6cb6a82ea9)
@@ -62,7 +62,7 @@
 
 
 def prepare_nc(trgFile, timeList, x, y, metadata, logger, EPSG="EPSG:4326", units=None,
-               calendar='gregorian', Format="NETCDF4", complevel=9, zlib=True, least_significant_digit=None):
+               calendar='gregorian', Format="NETCDF4", complevel=9, zlib=True, least_significant_digit=None,FillValue=1E31):
     """
     This function prepares a NetCDF file with given metadata, for a certain year, daily basis data
     The function assumes a gregorian calendar and a time unit 'Days since 1900-01-01 00:00:00'
@@ -91,7 +91,7 @@
     else:
         nc_trg.createDimension('time', 0)  # NrOfDays*8
 
-    DateHour = nc_trg.createVariable('time', 'f8', ('time',), fill_value=-9999., zlib=zlib, complevel=complevel)
+    DateHour = nc_trg.createVariable('time', 'f8', ('time',), fill_value=FillValue, zlib=zlib, complevel=complevel)
     DateHour.units = units
     DateHour.calendar = calendar
     DateHour.standard_name = 'time'
@@ -113,12 +113,12 @@
     if srs.IsProjected() == 0: # ONly lat lon needed
         nc_trg.createDimension('lat', len(y))
         nc_trg.createDimension('lon', len(x))
-        y_var = nc_trg.createVariable('lat', 'f4', ('lat',), fill_value=-9999., zlib=zlib, complevel=complevel)
+        y_var = nc_trg.createVariable('lat', 'f4', ('lat',), fill_value=FillValue, zlib=zlib, complevel=complevel)
         y_var.standard_name = 'latitude'
         y_var.long_name = 'latitude'
         y_var.units = 'degrees_north'
         y_var.axis = 'Y'
-        x_var = nc_trg.createVariable('lon', 'f4', ('lon',), fill_value=-9999., zlib=zlib, complevel=complevel)
+        x_var = nc_trg.createVariable('lon', 'f4', ('lon',), fill_value=FillValue, zlib=zlib, complevel=complevel)
         x_var.standard_name = 'longitude'
         x_var.long_name = 'longitude'
         x_var.units = 'degrees_east'
@@ -132,12 +132,12 @@
     else:  # Assume regular grid in m
         nc_trg.createDimension('y', len(y))
         nc_trg.createDimension('x', len(x))
-        y_var = nc_trg.createVariable('y', 'f4', ('y',), fill_value=-9999., zlib=zlib, complevel=complevel)
+        y_var = nc_trg.createVariable('y', 'f4', ('y',), fill_value=FillValue, zlib=zlib, complevel=complevel)
         y_var.standard_name = 'projection_y_coordinate'
         y_var.long_name = 'y-coordinate in Cartesian system'
         y_var.units = 'm'
         y_var.axis = 'Y'
-        x_var = nc_trg.createVariable('x', 'f4', ('x',), fill_value=-9999., zlib=zlib, complevel=complevel)
+        x_var = nc_trg.createVariable('x', 'f4', ('x',), fill_value=FillValue, zlib=zlib, complevel=complevel)
         x_var.standard_name = 'projection_x_coordinate'
         x_var.long_name = 'x-coordinate in Cartesian system'
         x_var.units = 'm'
@@ -449,6 +449,16 @@
         self.fstep = 0
         self.lstep = self.fstep + self.maxsteps
 
+        self.datetime = self.dataset.variables['time'][:]
+        if hasattr(self.dataset.variables['time'],'units'):
+            self.timeunits=self.dataset.variables['time'].units
+        else:
+            self.timeunits ='Seconds since 1970-01-01 00:00:00'
+        if hasattr(self.dataset.variables['time'], 'calendar'):
+            self.calendar= self.dataset.variables['time'].calendar
+        else:
+            self.calendar ='gregorian'
+        self.datetimelist=netCDF4.num2date(self.datetime,self.timeunits, calendar=self.calendar)
 
         try:
             self.x = self.dataset.variables['x'][:]
@@ -502,14 +512,15 @@
 
 
 
-    def gettimestep(self, timestep, logging, var='P', shifttime=False):
+    def gettimestep(self, timestep, logging, tsdatetime=None, var='P', shifttime=False):
         """
         Gets a map for a single timestep. reads data in blocks assuming sequential access
 
         :var timestep: framework timestep (1-based)
         :var logging: python logging object
         :var var: variable to get from the file
         :var shifttime: is True start at 1 in the NC file (instead of 0)
+        :var tsdatetime: Assumed date/time of this timestep
 
 
             window = data[dpos,latidx.min():latidx.max()+1,lonidx.min():lonidx.max()+1]
@@ -519,6 +530,10 @@
         else:
             ncindex = timestep - 1
 
+        if tsdatetime != None:
+            if tsdatetime != self.datetimelist[ncindex]:
+                logging.warn("Date/time does not match. Wanted " + str(tsdatetime) + " got " + str(self.datetimelist[ncindex]))
+
         if self.alldat.has_key(var):
             if ncindex == self.lstep:  # Read new block of data in mem
                 logging.debug("reading new netcdf data block starting at: " + str(ncindex))