[python #UVU-952934]: Problem downloading NAM_CONUS_12km data from conduit using siphon

Greetings!

This is a consequence of migrating to TDS v5. In that version, there had been 
changes to make the netCDF returns better comply with the netCDF CF 
conventions. Unfortunately, there's a bug right now where different "feature 
collections" are unable to be returned in a single file. Our THREDDS team is 
looking into it, but the fix is complicated and unlikely to be fixed soon.

The workaround for now is to make separate requests, which as you noticed can 
complete successfully.

Apologies for the inconvenience.

Ryan

> Hi,
> 
> Up until recently, I had a script running that was (successfully) grabbing 
> NAM_CONUS_12km data from conduit using siphon.  More recently, I have run 
> anew into an issue with the query.variables( ... ) part of the code.  The 
> below block worked in the past with no issue:
> 
> query.variables('Temperature_height_above_ground',
> 'Dewpoint_temperature_height_above_ground',
> 'u-component_of_wind_height_above_ground',
> 'v-component_of_wind_height_above_ground',
> 'Total_cloud_cover_entire_atmosphere_single_layer',
> 'Downward_Short-Wave_Radiation_Flux_surface',
> 'Precipitation_rate_surface_1_Hour_Maximum').accept('netcdf')
> 
> Now, when I run my code, I am receiving the error below.  I have struggled to 
> debug the issue.  I do know that it will now allow me to run the 
> query.variables portion with temperature and dewpoint only -or- the component 
> of winds only -or- the three remaining variables individually.  But, I cannot 
> query for them all at once anymore.  Is this an issue anyone else has been 
> known to encounter before?  Any guidance would be much appreciated.
> 
> 
> Error printout:
> 
> 
> HTTPError: Error accessing 
> https://thredds.ucar.edu/thredds/ncss/grid/grib/NCEP/NAM/CONUS_12km/conduit/NAM_CONUS_12km_conduit_20220913_0000.grib2?var=Temperature_height_above_ground&var=Dewpoint_temperature_height_above_ground&var=Downward_Short-Wave_Radiation_Flux_surface&var=Precipitation_rate_surface_1_Hour_Maximum&var=Total_cloud_cover_entire_atmosphere_single_layer&var=v-component_of_wind_height_above_ground&var=u-component_of_wind_height_above_ground&time_start=2022-09-13T00%3A00%3A00&time_end=2022-09-16T12%3A00%3A00&longitude=-94.36&latitude=49.79&accept=netcdf
> 
> Server Error (500: Throwable exception handled : 
> org.springframework.web.util.NestedServletException: Handler dispatch failed; 
> nested exception is java.lang.AssertionError: Multiple feature collections 
> cannot be written as a CF dataset
> 
> at 
> org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1082)
> 
> at 
> org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963)
> 
> at 
> org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
> 
> at 
> org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
> 
> 


Ticket Details
===================
Ticket ID: UVU-952934
Department: Support Python
Priority: Low
Status: Closed
===================
NOTE: All email exchanges with Unidata User Support are recorded in the Unidata 
inquiry tracking system and then made publicly available through the web.  If 
you do not want to have your interactions made available in this way, you must 
let us know in each email you send to us.