DAP4

This presentation was given at the 2014 OPeNDAP Developers Workshop that was held from 7-8 July 2014 in conjunction with the ESIP 2014 meeting in Frisco, CO. The intent of the workshop was to demonstrate and discuss diverse efforts related to the Data Access Protocol (DAP), with a special interest in how DAP and its applications were evolving.

Summary of this presentation: 

Representatives from OPeNDAP and Unidata discuss DAP4, which was developed to address flaws in DAP2 and advancements in related technologies like HDF5 and NetCDF4. The presentation defines DAP4  its specification, and releases of its servers and clients. DAP4's specification comprises two volumes covering the data model, web services, and extensions like CSV/Text and JSON responses. The data model introduces coverages, tabular data, projection, and filters. The web service is designed for simplicity and supports content negotiation and asynchronous responses. DAP4 emphasizes dataset metadata, data, and constraints. Despite budget cuts, the project is in good shape. Adoption use cases include subsetters, Giovanni for data exploration, MapServer for WMS services, NcML for aggregation, and netCDF-C for client applications, awaiting DAP4 support.