Figure.grdimage does not respect shading=None

[MarkWieczorek]

Description of the problem

Figure.grdimage() crashes when specifying the option shading=None. According to the docstring, shading=None is the default value, so this is weird. For the script I am using, I need to always specify something for shading (either nothing, or a file), so this breaks everything for me. This appears to have been broken since version 0.4

Full code that generated the error

This works

fig = pygmt.Figure()
fig.grdimage(grid="@earth_relief_01d_g")

fig = pygmt.Figure()
fig.grdimage(grid="@earth_relief_01d_g", shading="@earth_relief_01d_g+d")

This doesn't

fig = pygmt.Figure()
fig.grdimage(grid="@earth_relief_01d_g", shading=None)

Full error message

---------------------------------------------------------------------------
GMTInvalidInput                           Traceback (most recent call last)
Input In [10], in <cell line: 4>()
      1 import pygmt
      3 fig = pygmt.Figure()
----> 4 fig.grdimage(grid="@earth_relief_01d_g", shading=None)

File /opt/miniconda3/envs/testing/lib/python3.9/site-packages/pygmt/helpers/decorators.py:585, in use_alias.<locals>.alias_decorator.<locals>.new_module(*args, **kwargs)
    580         msg = (
    581             f"Short-form parameter ({short_param}) is not recommended. "
    582             f"Use long-form parameter '{long_alias}' instead."
    583         )
    584         warnings.warn(msg, category=SyntaxWarning, stacklevel=2)
--> 585 return module_func(*args, **kwargs)

File /opt/miniconda3/envs/testing/lib/python3.9/site-packages/pygmt/helpers/decorators.py:725, in kwargs_to_strings.<locals>.converter.<locals>.new_module(*args, **kwargs)
    723             kwargs[arg] = separators[fmt].join(f"{item}" for item in value)
    724 # Execute the original function and return its output
--> 725 return module_func(*args, **kwargs)

File /opt/miniconda3/envs/testing/lib/python3.9/site-packages/pygmt/src/grdimage.py:169, in grdimage(self, grid, **kwargs)
    166 file_context = lib.virtualfile_from_data(check_kind="raster", data=grid)
    167 with contextlib.ExitStack() as stack:
    168     # shading using an xr.DataArray
--> 169     if "I" in kwargs and data_kind(kwargs["I"]) == "grid":
    170         shading_context = lib.virtualfile_from_grid(kwargs["I"])
    171         kwargs["I"] = stack.enter_context(shading_context)

File /opt/miniconda3/envs/testing/lib/python3.9/site-packages/pygmt/helpers/utils.py:69, in data_kind(data, x, y, z, required_z)
     19 """
     20 Check what kind of data is provided to a module.
     21
   (...)
     66 'grid'
     67 """
     68 if data is None and x is None and y is None:
---> 69     raise GMTInvalidInput("No input data provided.")
     70 if data is not None and (x is not None or y is not None or z is not None):
     71     raise GMTInvalidInput("Too much data. Use either data or x and y.")

GMTInvalidInput: No input data provided.

System information

macos and ubuntu.

[seisman]

Likely a duplicate of #1665.

[weiji14]

Yes, this seems related to the bug mentioned at #1665 (comment). A workaround to keep you going would be to use shading=False for now.

Also @MarkWieczorek, could you please post the output of python -c "import pygmt; pygmt.show_versions()" so that we have a record on which PyGMT version this is a problem on?

[MarkWieczorek]

And this, I think: #1815

[MarkWieczorek]

pyGMT information:
  version: v0.6.0
System information:
  python: 3.9.12 | packaged by conda-forge | (main, Mar 24 2022, 23:23:20)  [Clang 12.0.1 ]
  executable: /opt/miniconda3/envs/testing/bin/python
  machine: macOS-12.2.1-x86_64-i386-64bit
Dependency information:
  numpy: 1.22.3
  pandas: 1.4.1
  xarray: 2022.3.0
  netCDF4: 1.5.8
  packaging: 21.3
  ghostscript: 9.54.0
  gmt: 6.3.0
GMT library information:
  binary dir: /opt/miniconda3/envs/testing/bin
  cores: 24
  grid layout: rows
  library path: /opt/miniconda3/envs/testing/lib/libgmt.dylib
  padding: 2
  plugin dir: /opt/miniconda3/envs/testing/lib/gmt/plugins
  share dir: /opt/miniconda3/envs/testing/share/gmt
  version: 6.3.0

[MarkWieczorek]

shading=False works for now. It is just that this isn't consistent with the documentation, so this should probably get fixed at some point.