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OPeNDAP software

An OPeNDAP Server for in-situ and gridded data


This page is no longer maintained. All Dapper documentation is now available at www.dchart.org, including news on the latest releases in the forum, and documentation on installation and configuration.

What is dapper?

Dapper is an OPeNDAP web server developed by the EPIC group at PMEL that provides networked access to in-situ and gridded data. With Dapper, OPeNDAP enabled clients now have remote access to millions of previously unavailable in-situ oceanographic or atmospheric observations.

The Dapper server distribution also includes a web interface called DChart. DChart has interactive controls similar to those in Google Maps, and, like Google Maps, is based AJAX. Click here to try it or view a Flash movie of DChart in action.

What problem does dapper address?

The major strength of previous OPeNDAP-enabled data servers has been in providing access to a relatively small number of large gridded datasets or model results. The strategies required for successfully identifying a large gridded data set, subsetting the grid, and transporting the data to a remote client are quite different from those required for in-situ collections containing very large numbers of individual files. In-situ data collections can contain vast numbers of individual (more than one million) profiles or time series.

What is the solution?

Dapper is a Java servlet that contains a set of configurable services that convert in-situ or gridded data to the OPeNDAP protocol. The servlet can easily be embedded in any Web server that implements the Java servlet API (such as Jetty or Tomcat).

The new "dapper" in-situ data server utilizes OPeNDAP-standards consistent with the GDS in-situ data server implementation. Together, the "dapper" and GDS in-situ data servers make a very wide assembly (or compilation) of in-situ data collections available through OPeNDAP.

See the initial version of the Dapper In-situ Data Conventions that are used for representing in-situ data in OPeNDAP, available at

Where is dapper installed?

The "dapper" server has been installed for

How do I install Dapper?

Download and installation information for Dapper is available here.

Dapper clients

Clients for in-situ data served with dapper include:

  • DChart, an AJAX Web application for Dapper
  • ncBrowse - Networking desktop Java application that provides flexible, interactive, graphical displays of data and attributes from a wide range of netCDF and OPeNDAP data file conventions. Dapper is supported in release 1.5.0Beta3
  • Grid Analysis and Display System (GrADS) - An interactive desktop tool that is used for easy access, manipulation, and visualization of earth science data. Dapper will be supported by GrADS version 1.9.
  • matlab - reads OPeNDAP data into matlab
  • Java OceanAtlas - Interactive desktop Java application for viewing and manipulating ocean profile data. See the JOA Home Page and the EPIC users page for JOA. Dapper support soon - in the next test release.
  • OceanShare - Interactive, networking Java collaboration tool built on the CDP. On-the-fly production of integrated browse images from in situ datasets stored at two or more geographically-distributed data archives, and allows two or more scientists at different locations to view these images and have annotations simultaneously appear on all collaborating scientists desktops. All collaborating scientists can interactively post messages and change the data being displayed. Dapper support soon - in the next test release.
  • LAS - Contact the LAS team.

Clients for gridded data served with dapper include:

Dapper Demonstrations

References & More Information


For more information, please contact Joe Sirott at Joe.NOSPAM.Sirott@noaa.gov.NOSPAM and see the EPIC software license agreement.