issue_comments: 222995827

On further investigation, it appears the problem is the dataset contains a mix of string and float data - the strings are redundant representations of the time stamp, therefore they don't appear in the index query. When I tried to convert to array, the numpy chokes on the mixed types. Explicitly selecting on the desired data variable solves this:

selection = cfsr_new.TMP_L103.sel(lon=lon_sel, lat=lat_sel, time=time_sel)

I think a clearer error message may be needed: when you do sel without indexing on certain dimensions, those are included in the resulting selection. It's possible for those to be of mixed incompatible types. Clearly to do to_array you need a numpy-friendly uniform type. The error should make this clearer.