Lately I have been working on an extension to THREDDS so you can do OpenDap style queries on NetCDF files but return a JSON format instead. Specifically so you can have a Google Visualization Source JSON format returned. Currently THREDDS allows easy access to OpenDap forms like this, I have created a dataset access form for creating the visualization source query here. This form can be used to create and test queries. I will be working to integrate this form into the THREDDS catalog page as an access type.
We (my lab) are hoping this will be useful for pushing scientific datasets, among other things, to the web as well as adding the ability to quickly create online visualizations for these datasets. The google visualization source json protocol is a simple protocol with an extensive library of widgets behind it. Creating new visualizations in JavaScript or tools such as GWT is relatively easy as well.
