Document the GVRS file format, introduce some revisions

[gwlucastrig]

I am currently writing a specification document for the GVRS File Format. To document the GVRS format, I am converting my hand-written notes into a Word document and adding text to clarify the underlying concepts.

Changes to the GVRS format
One of the consequences of this kind of review is that has revealed a few shortcomings in the existing specification. Therefore, I am also making changes to some aspects of the format. The revised format will be designated version 1.4. The Java-based API will be changing to write data in the new format. So far, I have been able to maintain the ability for the API to read files written in the 1.2 format. Frankly, I am not really sure that maintaining backwards compatibility is worth the effort. So far, the GVRS user base remains very small and I am unaware of anyone who has invested effort in creating GVRS data products.

I welcome feedback regarding this issue. If you have any questions about the GVRS format, please let me know.

As a preview, I've attached one of the diagrams from the document to illustrate the overall structure of the GVRS format.

[gwlucastrig]

I have posted a preliminary draft of the GVRS file format specification version 1.4.

You may view it at https://gwlucastrig.github.io/GridfourDocs/notes/GvrsFileFormat_1_04.pdf

In conjunction with this effort, I am preparing a new release of the GVRS software.

Finally, the document is a preliminary draft. If you find any errors (technical or typographical), or have suggestions for improvements, please let me know.

Thanks.

Gary

[gwlucastrig]

The Version 1.0.4 release of Gridfour includes the updates to the grid format specification.

With the Gridfour 1.0.4 release, version 1.4 of the GVRS file format will be treated as stable going forward. The API will continue to support the earlier 1.2 version of the file format on a read-only basis. But that feature may be retired in the future.