das2 logo spectrogram

das2 is the second-generation web-based data delivery, visualization, and analysis system from the The University of Iowa. Data are transmitted to clients along with software to manipulate and display the data.

The Design of das2

Das2 consists of several components. Various Java libraries and client-side applications support space science data visualization such as interactive spectrograms, overlays, waveform plots, etc. Distributed data servers and server-side applications here at Iowa and other sites provide self-describing data streams to the client applications. Our IHDEA 2020 video presentation provides a good overview.

Multi-Resolution Data Servers

Das2 servers conserve network bandwith by providing self-describing streams of data at a resolution matched to the output device.

Das2 federated catalogs provide a location-independent registry of data sources. Browse the federated catalog of accessible data.

Open Source Projects

das2java is the Java Swing GUI library used by Autoplot, MIDL and special applications. Das2Core provides client-side data operations such as:

It's available as a Netbeans project, though may be built via ant.

das2C is a portable C-library and utilities which handle much of the server-side data reduction and transformation and provides connectivity for SDDAS.

das2-pyserver is a python replacement for the original perl based server that adds a pre-reduced cache for better performance.

das2py is an efficient python module that loads data directly into NumPy arrays via a C extension. It is based on das2C.

das2pro is a pure IDL das2 client which requires IDL 8.6 and above.

das2dlm is an IDL dynamically loadable module that includes das2C and requires IDL 8.0 and up.

Interactive Plots and Analysis

Portable Java Clients provide an interactive plotting experience. As you browse datasets via zoom, pan and slice operations, new values are automatically downloaded at an appropriate resolution from the server.

Autoplot is the most popular das2 client and plots data from many sources. In addition to its role as a graphical data browser, Autoplot exposes a scripting interface for creating custom interactive displays.

Small demo applications provide custom features for selected data sources.

SPEDAS 4.0 adds support for das2 servers using das2dlm.

Presentations and Programmer Documents

Our 2017 AGU poster provides a das2 system overview, although it's weighted a bit towards server design.

Our 2018 AGU poster provides an overview of non-java clients, and touches on VESPA integration.

Our 2019 AGU poster provides an overview of data source location resolution using the catalog.

The Das2 2.2 Interface Control Document adds sequence yTags attributes to allow for shorter waveform headers.

The Das2 2.3 Interface Control Document (in process) cleans up das2 stream headers and removes internal das2-pyserver details.

MIME types for das2 streams and the top level tag URI can be found on the stream verification page (in process).

View the das2 Issues database on github.

das Classic

The first-generation das1 delivers data products via gif images. Data product parameters were set with html forms.

We recommend OpenJDK Python Created with NetBeans NetBeans
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"Sad backwards is das" — Carroll County Veterinary Clinic