Problems with xarray broadcasting/dimensions #2069
Description
I've encountered pretty easily some challenges trying to use XArray-based data, specifically when pulling out 1D pressure coordinates to use as a data field. I was able to easily fix heat_index by adding broadcast to the preprocess_and_wrap decorator, but I haven't quickly figured out this one with dewpoint_from_specific_humidity:
import xarray as xr
import metpy.calc as mpcalc
from metpy.cbook import get_test_data
narr = xr.open_dataset(get_test_data('narr_example.nc', as_file_obj=False))
dewp = mpcalc.dewpoint_from_specific_humidity(narr.isobaric, narr.Temperature, narr.Specific_humidity)This gives:
ValueError Traceback (most recent call last)
/var/folders/r8/bhrhn4m56lgdckj491rm6_w40000gp/T/ipykernel_48975/3495402994.py in <module>
----> 1 dewp = mpcalc.dewpoint_from_specific_humidity(narr.isobaric, narr.Temperature, narr.Specific_humidity)
~/repos/metpy/src/metpy/xarray.py in wrapper(*args, **kwargs)
1232 return tuple(wrapping(*args) for args in zip(result, match))
1233 else:
-> 1234 return wrapping(result, match)
1235 return wrapper
1236 return decorator
~/repos/metpy/src/metpy/xarray.py in _wrap_output_like_not_matching_units(result, match)
1288 result = units.Quantity(result)
1289 return (
-> 1290 xr.DataArray(result, coords=match.coords, dims=match.dims) if output_xarray
1291 else result
1292 )
~/miniconda3/envs/py39/lib/python3.9/site-packages/xarray/core/dataarray.py in __init__(self, data, coords, dims, name, attrs, indexes, fastpath)
408 data = _check_data_shape(data, coords, dims)
409 data = as_compatible_data(data)
--> 410 coords, dims = _infer_coords_and_dims(data.shape, coords, dims)
411 variable = Variable(dims, data, attrs, fastpath=True)
412 indexes = dict(
~/miniconda3/envs/py39/lib/python3.9/site-packages/xarray/core/dataarray.py in _infer_coords_and_dims(shape, coords, dims)
156 for d, s in zip(v.dims, v.shape):
157 if s != sizes[d]:
--> 158 raise ValueError(
159 f"conflicting sizes for dimension {d!r}: "
160 f"length {sizes[d]} on the data but length {s} on "
ValueError: conflicting sizes for dimension 'time': length 29 on the data but length 1 on coordinate 'time'It's also disconcerting to see this warning:
/Users/rmay/repos/metpy/src/metpy/calc/thermo.py:1047: UserWarning: Relative humidity >120%, ensure proper units.
warnings.warn('Relative humidity >120%, ensure proper units.')