I ran a file with the following header through the compliance checker and got
these errors:
```
ERROR: (7.3): Invalid 'name' in cell_methods attribute: lon
ERROR: (7.3): Invalid 'name' in cell_methods attribute: lat
```
the header:
```java
netcdf burst.nc {
dimensions:
ntimeMax = 18857983;
timeSeries = 5;
variables:
int timeSeries(timeSeries);
:long_name = "Unique identifier for each feature instance";
:cf_role = "timeseries_id";
double time(timeSeries, ntimeMax);
:units = "days since 0001-01-01 00:00:00 -0:00";
:calendar = "proleptic_gregorian";
:long_name = "Time";
:standard_name = "time";
:axis = "T";
double lat(timeSeries);
:valid_min = -90.0;
:valid_max = 90.0;
:long_name = "Latitude";
:standard_name = "latitude";
:units = "degrees_north";
:axis = "Y";
double lon(timeSeries);
:standard_name = "longitude";
:units = "degrees_east";
:axis = "X";
:valid_min = -180.0;
:valid_max = 180.0;
:long_name = "Longitude";
int pressure(timeSeries, ntimeMax);
:units = "decibar";
:long_name = "Sum of atmospheric pressure and sea pressure";
:standard_name = "sea_water_pressure";
:scale_factor = 1.0E-4;
:coordinates = "time lat lon";
:coverage_content_type = "physicalMeasurement";
:grid_mapping = "crs";
:cell_methods = "time: point lon: point lat: point";
int crs;
:grid_mapping_name = "latitude_longitude";
:epsg_code = "EPSG:4326";
:semi_major_axis = 6378137.0;
:inverse_flattening = 298.257223563;
// global attributes:
:featureType = "timeSeries";
...and so on
}
```
For background, my file is based on the [NCEI
template](https://www.nodc.noaa.gov/data/formats/netcdf/v2.0/) for timeSeries
Incomplete data, which gives `"time: point lon: point lat: point"` as an
example for cell_methods. Reading [CF 7.3]
(https://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html#cell-methods),
it looks like the `name` part of the cell method can be:
> a dimension of the variable, a scalar coordinate variable, a valid standard
> name, or the word "area".
For discrete sampling geometry data like the above example, although I have
time, lat, and lon variables in the file, the data variable is dimensioned by
`(timeSeries, ntimeMax)`, so the way I'm reading it, it is invalid to use time,
lat, or lon as the name part of a cell method. I suppose one way to look at
it is, there isn't really a notion of a cell in space in this example since
these are discrete locations. However, you could have a cell method for the
time dimension, which is perhaps why the checker didn't raise an error about
`time: point`? But `time` isn't the name of the one of the dimensions of the
data variable, so it should still fail according to 7.3, right?
Elucidation would be much appreciated. Once I have a clearer picture, I'd be
happy to advise NCEI on how to update the examples in their templates.
Thanks!
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