Extracting NetCDF raster values to time enabled shapefiles - what's wrong with my python script?

Question

I'm trying to make a python script tool that extracts the values from a NetCDF raster to each data point from a time enabled shapefile at the correct time. My NetCDF raster consists of monthly sea surface temperature (SST) averages and I also have a plastic debris point shapefile that has been time enabled with time step interval of one month. I have checked with Time Slider that both the raster and the shapefile values change through time correctly.

Can someone please help me figure out why I keep getting an error with this script:

mxd = arcpy.mapping.MapDocument('SST.mxd')
df = arcpy.mapping.ListDataFrames(mxd)[0]
rasterLayerName = "SST"
rasterLayer = arcpy.mapping.ListLayers(mxd, rasterLayerName, df)[0]
plasticLayerName = "Plastic"
plasticLayer = arcpy.mapping.ListLayers(mxd, plasticLayerName, df)[0]
df.time.currentTime = df.time.startTime
while df.time.currentTime <= df.time.endTime:
   uniqueName = "Plastic_" + df.time.currentTime.strftime("%Y_%m")
   outPointFeatures = "U:/gis/" + uniqueName
   arcpy.sa.ExtractValuesToPoints(plasticLayer, rasterLayer,
         outPointFeatures, "NONE", "VALUE_ONLY")
df.time.currentTime += df.time.timeStepInterval

Here is the error:

Runtime error
  Traceback (most recent call last):
   File "<string>", line 6, in <module>
   File "c:\program files (x86)\arcgis\desktop10.1\arcpy\arcpy\sa\Functions.py", line 1311, in ExtractValuesToPoints
     add_attributes)
   File "c:\program files (x86)\arcgis\desktop10.1\arcpy\arcpy\sa\Utils.py", line 47, in swapper
     result = wrapper(*args, **kwargs)
   File "c:\program files (x86)\arcgis\desktop10.1\arcpy\arcpy\sa\Functions.py", line 1304, in wrapper
     add_attributes)
   File "c:\program files (x86)\arcgis\desktop10.1\arcpy\arcpy\geoprocessing\_base.py", line 498, in <lambda>
     return lambda *args: val(*gp_fixargs(args, True))
 ExecuteError: ERROR 001143: Background server threw an exception.

I'm using ArcGIS Desktop 10.1 and Python 2.7 on Windows 7.

Answer 1

It appears as though you have background geoprocessing for your script enabled. Disable background geoprocessing for this tool and try running it again.

Additionally, you are introducing an infinite loop in your script. Change your while loop to include the df.time.currentTime += df.time.timeStepInterval snippet:

while df.time.currentTime <= df.time.endTime:
   uniqueName = "Plastic_" + df.time.currentTime.strftime("%Y_%m")
   outPointFeatures = "U:/gis/" + uniqueName
   arcpy.sa.ExtractValuesToPoints(plasticLayer, rasterLayer,
                                  outPointFeatures, "NONE", "VALUE_ONLY")
   df.time.currentTime += df.time.timeStepInterval