161 spatial metrics

[havardhhaugen]

This pr implements a new output class Spatial, from which specific spatial outputs can subclass. The Spatial class is intended for outputs which do some sort of spatial operation, and it writes outputs as netcdf files with dimensions (time, leadtime, ensemble_member, *metric_specific_dimensions).

So far I have implemented two spatial outputs:

• powerspectrum_global (used for global grids)
• powerspectrum_gridded (used for regular projected grids)

Example config

routing:
  - decoder_index: 0
    domain_index: 0
    outputs:
      - powerspectrum_global:
          filename: ${ps_dst_folder}/ps_n320_ws.nc
          variable: ws

Introduces a new dependency pyshtools (used to calculate spherical harmonics fourier transform)

[havardhhaugen]

Tests failing because pyshtools is missing from the test environment, I don't know where to fix that.

[ways]

Tests failing because pyshtools is missing from the test environment, I don't know where to fix that.

Added.

[ways]

No comments. I'd love a tox test (with config and necessary test data). For debugging, avoiding regressions and as example usage.

[havardhhaugen]

No comments. I'd love a tox test (with config and necessary test data). For debugging, avoiding regressions and as example usage.

I made unit tests for the two new outputs, and I'll update the documentation once this has been merged.

[havardhhaugen]

Good to merge this?