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  1. Overview
  2. History
  3. Links
  4. Points of Clarification

1. Overview

This is a page for the developers working on the TSDS project (Time Series Data Server/Services) and HPDE-DAP (Heliophysics Data Environment Data Access Protocol). TSDS software and the HPDE-DAP will be co-developed.

This page will be used for two purposes:

  1. Discussion of the HPDE Data Access Protocol (i.e., syntax for a REST API for time series-like data)
  2. Development notes for software that implements the HPDE-DAP.

2. History

The TSDS project was originally supported by ViRBO and was designed by Lindholm, Weigel, Wilson, and Faden. An early Octave/Perl implementation by Weigel was replaced by a Java implementation by Lindholm and Wilson in 2009/2010. Support from ViRBO ended in 2010, but development continued at LASP (by Lindholm and Wilson). Starting in Spring 2011, development will be supported by HPDE and the LASP LISIRD project.

3. Links

4. Points of Clarification

  • The "TSDS" name has taken on several meanings over the years:
    • tsds = ("Time Series Data Sets") An initial software project for analysis and creation of a large time series data set for data mining [3], which had an associated server [4] (Weigel).
    • TSDS = "Time Series Data Server" discussed in a proposal [5] and paper [6].
    • TSS = A modular Java Servlet-based OPeNDAP server built around the Netcdf-Java implementation [7] of the Unidata Common Data Model [8] and the NetCDF Markup Language (NcML) for serving time series data (Lindholm and Wilson). Currently maintained at
    • TSS2 = TSS with the NetCDF data model implementation replaced with an experimental Time Series Data Model and re-purposed Time Series Markup Language (TSML). Currently under development at LASP as part of the LaTiS service that supports LISIRD.

I suggest that we use the following conventions

  • TSDS = Umbrella project and software system that includes (Time Series Data System)
    • The TSS data server and core modules maintained at [9]
    • TSS modules to provide TSDS-specific capabilities for reading, writing, and filtering data
    • An API specification component (HPDE-DAP)


The following is the relevant section from the proposal that is to be discussed by the HPDE DAP working group. (Note that this text was extracted from the proposal and the reference section numbers and tasks are relative to the proposal document [10])

In this section, we describe the proposed API. A draft API specification will be sent out for comment to the SPASE, SMWG (SPASE Metadata Working Group), and HPDE (Heliophysics Data Environment) email lists within a month after the project start date. (Note that throughout this proposal, for clarity, we used an API syntax that is simpler than the one discussed below. At this point we will not specify a final syntax; a major part of the proposed effort will be in working with members of the Heliophysics and Earth Sciences community to identify the most appropriate syntax.)

The base-line OPeNDAP-compliant syntax discussed in section 3.1 below has already been implemented for a certain subset of data and was developed as a part of the initial support of the Virtual Radiation Belt Observatory (ViRBO) project. The TSDS software was one of the three major software packages developed to enable virtual observatories and data providers to easily provide services on data and/or metadata in their domain.

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