Development of improved Hyrax User Interfaces

From OPeNDAP Documentation
Revision as of 20:20, 2 April 2010 by Ndp (talk | contribs)
⧼opendap2-jumptonavigation⧽

Development of Improved User Interfaces for Hyrax

The Hyrax data server provides one of the simplest User Interfaces (UIs) that OPeNDAP supports. While it has not undergone any significant change in almost a decade, that interface remains one of the most widely used with which to access data using our server. In the intervening time since it was first implemented, many new technologies have emerged which greatly expand the capabilities of a web-based UI. In this proposal we outline the enhancements possible to this popular interface (known as the ‘HTML form interface’ as well as more colorful names) and the benefits those enhancements would bring to users.

Why the ‘HTML Form Interface’ is so important:

  • Ubiquitous: The interface is part of the server so it is always present
  • It can work with any data served: It is the LCD of UIs


Features

What features are proposed for the interface?

  • The interface (UI) will recognize geo-referenced Grid variables; present a map, a time line and use geogrid() functions when building requests
  • The UI will also recognize geo-referenced Arrays and enable Grid-like selection capabilities using values gleaned from DAP attributes
  • UI will use AJAX where it can to be more interactive
  • Add time as a recognized type in the UI (at least)
  • The UI will examine a server and suggest using an aggregation if the data set currently viewed is part of one hosted by that server (does not check for an aggregation managed by a remote server).
  • The UI will reduce clutter to improve the display of large data sets (using AJAX) and other techniques.

New server features will further increase the interface’s usefulness

  • The netCDF file output means that the UI can deliver data in a form that is more easily used. Currently the data are delivered in DAP binary form, something that only a handful of clients can use. The netCDF file response will expand the set of ‘clients’ to all of the software that can read netCDF files (this was added and released as part of Hyrax 1.5 in early April 2009).
  • Expanded server-side functions will simplify writing complex Constraint Expressions. Much of the data served by DAP is geospatial data but its storage precludes easily using it as such. The new server-side functions will provide a new interface which greatly simplify this use
  • Aggregation will enable the server to collapse certain operations that used to take several ‘trips’ to the server into a single request which makes a form interface, which is fundamentally non-interactive, easier to use.