Support other data representation templates

[kubovy]

Currently this library supports only "Grid Point Data - Complex Packing and Spatial Differencing". It would be useful to support more than this one to enable reading GRIB2 files from e.g. NOMAD which use "Grid Point Data - Simple Packing".

Documentation can be found: https://www.yumpu.com/en/document/view/11723135/guide-to-wmo-table-driven-code-forms

The "Grid Point Data - Simple Packing" is rather simple. "Grid Point Data - Complex Packing" is more complex but as it is a base for the already implemented "Grid Point Data - Complex Packing and Spatial Differencing" this should also be feasable.

[spidru]

Hi @kubovy, there are indeed plans to support more data representation formats. At the moment I'm working on improving the CI to cross-check all data values against a well-known reference (e.g. wgrib/wgrib2). Once this is in place, support for more data representation formats can follow.

[kubovy]

I did my research here an the implementation of Grid Point Data - Complex Packing without Spatial Differencing (section 5.2) is rather simple. Also the Grid Point Data - Simple Packing is relatively easy. Both are also included in the draft PR #13