Possible changes to GVRS file format to support multiple data sets

[gwlucastrig]

I am thinking about enhancing the GVRS file format to support multiple data sets (including rasters with different data types, sizes and resolutions) in a mannr similar to HDF5 (NetCDF) and TIFF. This action would break compatibility with existing file products. So I need to figure out how to proceed without breaking code for existing users.

If you are currently using GVRS, I invite you to post a quick note telling me about how you use it. That information will help me plan future work more effectively.

I also welcome suggestions for new features and how the code could make the transition to the new format without too major an impact on existing users.

[gwlucastrig]

If this change would affect your work, please let me know. I am currently implementing the revised GVRS data format. I would prefer to not worry about backward compatibility (and the "technical debt" that comes with it).

I have the impression that my user base is small and no one will be negatively affected by this change. However, I do not want to make extra work for anyone. So if you are currently using GVRS, we can discuss the best way forward.

One of the new features that these changes will support is the ability to implement a pyramid structure to provide multiple resolutions for terrestrial and ocean data.

I am also looking to introduce some minor improvements to the data compression logic which I hope will improve speed and compression ratios.

Finally, note that I am simultaneously maintaining the C-language version of the GVRS API. I will coordinate future changes.