Activity

1. dcamron

   self-assigned this

   on Feb 22, 2023
2. dcamron commented on Feb 22, 2023

   

   dcamron

   on Feb 22, 2023

   Member

   More actions

   That example is very out of date, as are many others on this repository at this moment. Please explore examples in the MetPy docs example gallery instead until we close this issue.

   I can still help from here. That function signature has been updated a few times since, check out the documentation or in your particular python install (here, the latest version of MetPy, 1.4) with:

   >>> import metpy.calc as mpcalc
   >>> help(mpcalc.geostrophic_wind)
   Help on function geostrophic_wind in module metpy.calc:
   
   geostrophic_wind(height, dx=None, dy=None, latitude=None, x_dim=-1, y_dim=-2, *, parallel_scale=None, meridional_scale=None, longitude=None, crs=None)
       Calculate the geostrophic wind given from the height or geopotential.
   ...

   where we can see that the inputs I'm providing my function don't match up. So, on MetPy 1.4, that particular line could be re-written (without any other changes) as

   geo_wind_u, geo_wind_v = mpcalc.geostrophic_wind(height * units.m, dx=dx, dy=dy, latitude=lat_2d)

   ---

   Since MetPy 1.4, there are few ways you can do this without calculating dx, dy by hand, and if you're using xarray you can simplify this much further!

   ...  #continued from the original example
   data = ncss.get_data(query)
   
   import xarray as xr
   ds = xr.open_dataset(xr.backends.NetCDF4DataStore(data))
   
   geo_wind_u, geo_wind_v = mpcalc.geostrophic_wind(ds['Geopotential_height_isobaric'])

   Note, if you use xarray with your own netcdf files, or most remote data not accessed using NCSS + netcdf4-python (as in this example), you won't need the xr.backends.NetCDF4DataStore bit, and your script might just look like

   import metpy.calc as mpcalc
   import xarray as xr
   
   ds = xr.open_dataset('my_data.nc')
   
   mpcalc.geostrophic_wind(my_data['my_height_variable'])

   🎉 Hope this helps. Please start a new discussion here if you have further issues or visit the other MetPy support venues if needed. Be sure to update your install of MetPy!
3. takayanamba99 commented on Feb 24, 2023

   

   takayanamba99

   on Feb 24, 2023

   Author

   More actions

   Thank you for the suggestion.
   It seems to work on the part below you suggested
   After the part, on # Create new figure
   the error took place and didn't make the same figures (without geostrophic and ageostrophic winds)

   The part you suggested seems to work

   import xarray as xr
   ds = xr.open_dataset(xr.backends.NetCDF4DataStore(data))
   geo_wind_u, geo_wind_v = mpcalc.geostrophic_wind(ds['Geopotential_height_isobaric'])
   geo_wind_u = geo_wind_u
   geo_wind_v = geo_wind_v

   Calculate ageostrophic wind components

   ageo_wind_u = u_wind - geo_wind_u
   ageo_wind_v = v_wind - geo_wind_v

   ================== # Create new figure
   An error took place as

   ValueError Traceback (most recent call last)
   in
   32 u_wind[quiver_slices], v_wind[quiver_slices],
   33 color='blue', **quiver_kwargs)
   ---> 34 geo = ax.quiver(lon_2d[quiver_slices], lat_2d[quiver_slices],
   35 geo_wind_u[quiver_slices], geo_wind_v[quiver_slices],
   36 color='darkorchid', **quiver_kwargs)

   /opt/miniconda3/lib/python3.9/site-packages/cartopy/mpl/geoaxes.py in wrapper(self, *args, **kwargs)
   316
   317 kwargs['transform'] = transform
   --> 318 return func(self, *args, **kwargs)
   319 return wrapper
   320

   /opt/miniconda3/lib/python3.9/site-packages/cartopy/mpl/geoaxes.py in quiver(self, x, y, u, v, *args, **kwargs)
   2092 x, y = np.meshgrid(x, y)
   2093 u, v = self.projection.transform_vectors(t, x, y, u, v)
   -> 2094 return super().quiver(x, y, u, v, *args, **kwargs)
   2095
   2096 @_add_transform

   /opt/miniconda3/lib/python3.9/site-packages/matplotlib/init.py in inner(ax, data, *args, **kwargs)
   1445 def inner(ax, *args, data=None, **kwargs):
   1446 if data is None:
   -> 1447 return func(ax, *map(sanitize_sequence, args), **kwargs)
   1448
   1449 bound = new_sig.bind(ax, *args, **kwargs)

   /opt/miniconda3/lib/python3.9/site-packages/matplotlib/axes/_axes.py in quiver(self, *args, **kw)
   5019 args = self._quiver_units(args, kw)
   5020
   -> 5021 q = mquiver.Quiver(self, *args, **kw)
   5022
   5023 self.add_collection(q, autolim=True)

   /opt/miniconda3/lib/python3.9/site-packages/matplotlib/quiver.py in init(self, ax, scale, headwidth, headlength, headaxislength, minshaft, minlength, units, scale_units, angles, width, color, pivot, *args, **kw)
   472 """
   473 self._axes = ax # The attr actually set by the Artist.axes property.
   --> 474 X, Y, U, V, C = _parse_args(*args, caller_name='quiver()')
   475 self.X = X
   476 self.Y = Y

   /opt/miniconda3/lib/python3.9/site-packages/matplotlib/quiver.py in _parse_args(caller_name, *args)
   417 f'{len_args} were given')
   418
   --> 419 nr, nc = (1, U.shape[0]) if U.ndim == 1 else U.shape
   420
   421 if X is not None:

   ValueError: too many values to unpack (expected 2)

   Could you give me any suggestions for this issue?