Could NCSS handle integrated data with no coverage (integrated point data) ?

[PBrockmann]

I have a netCDF resource with no coverage metadata (no longitude, latitude) because it contains integrated quantities (global or regional means for example).

In this case, the NCSS complains with
err=Could not open as Coverage

https://vesg.ipsl.upmc.fr/thredds/ncss/point/work_thredds/p86pasb/IPSLCM6/PROD/lig127k/CM61LIG127k00/MONITORING/files/ATM_precip_land_ave.nc?var=T2M_GLOBAL_PRIOtemporal=all&accept=csv
returns a zero size file.

The OPeNDAP service is available from:
https://vesg.ipsl.upmc.fr/thredds/dodsC/work_thredds/p86pasb/IPSLCM6/PROD/lig127k/CM61LIG127k00/MONITORING/files/ATM_precip_land_ave.nc.html

and the header of this file is:

variables:
        double TIME_COUNTER(TIME_COUNTER) ;
                TIME_COUNTER:axis = "T" ;
                TIME_COUNTER:long_name = "Time axis" ;
                TIME_COUNTER:calendar = "gregorian" ;
                TIME_COUNTER:units = "seconds since 1850-01-01 00:00:00" ;
                TIME_COUNTER:time_origin = "1850-01-01 00:00:00" ;
                TIME_COUNTER:bounds = "TIME_COUNTER_bnds" ;
                TIME_COUNTER:standard_name = "time" ;
        double TIME_COUNTER_bnds(TIME_COUNTER, bnds) ;
        double T2M_GLOBAL_PRIO(TIME_COUNTER) ;
                T2M_GLOBAL_PRIO:missing_value = -1.e+34 ;
                T2M_GLOBAL_PRIO:_FillValue = -1.e+34 ;
                T2M_GLOBAL_PRIO:long_name = "Temperature at 2 meters (GLOBAL)" ;
                T2M_GLOBAL_PRIO:units = "degrees C" ;

[cofinoa]

Hi @PBrockmann,

As you have checked, the NCSS expects a CDM files with spatial and temporal (?) coverage.

You can try to add a geo reference system.

For example a 1-dimensional longitude and latitude coordinates with just 1 value on each (i.e. the center of the global bounding-box).

Antonio

P.S: I haven't test this case with NCSS, when coordinates only contains one-value, therefore feedback it's welcome.

[PBrockmann]

Hi @cofinoa,
thank you for your interest in this issue.

In the concerned project, the resource does not include spatial description unfortunately. But in another project, I have indeed be carefull to include a false lon, lat to get rid off this "limitations" and it works.

Here is an example that works with 'false' longitude latitude coordinates set to 0.
http://www.globalcarbonatlas.org/thredds/ncss/grid/Atlas/Flux_Transcom/EUROCOM/yearlymean/regions/region07/fco2_CHIMERE-VPRMv1_June2018-ext3_2006-2015_yearlymean_region07.nc?var=Terrestrial_flux&latitude=0&longitude=0&temporal=all&accept=csv

So my purpose would be to change NCSS to be able to handle those cases where describing a longitude, latitude is not relevant. Because spatial integrations are often made on regions defined by shapefiles, define a longitude and a latitude is not very adapted (even if possible by taking the center of the shapefile).

Do you thing it could be possible ?

[PBrockmann]

BTW, the temporal=all seems to be missing in the NCSS interface. Should be another issue, I agree.