84th AMS Annual Meeting

Monday, 12 January 2004
Serving the NODC/OCL World Ocean Database via the Live Access Server (LAS)
Hall 4AB
Joseph McLean, JISAO/University of Washington, Seattle, WA
Poster PDF (264.8 kB)
The Live Access Server is a Web-server designed to provide access to geo-referenced scientific data. In its basic form, a user is presented with an interface through a web browser with which he can select various datasets, variables, XYZT subsets of data, and products. LAS then accesses the data locally or remotely via OPeNDAP and creates "on-the-fly" products which are returned to the user's browser.

The National Oceanographic Data Center/Ocean Climate Laboratory (NODC/OCL ) World Ocean Database 2001 (WOD01) is a collection of ocean profile data comprising over 7 million stations and hundreds of millions of individual data measurements. The data include metadata such as Location, Cruise ID, Project affiliation, Institution affiliation, Quality flags etc. Standard presentation of the data is a set of eight CD-ROMS containing OCL formatted ASCII files representing nearly 14 gb of data.

The origins of LAS focussed on providing access to data gridded on a subset of the 4 axes: Longitude, Latitude, Depth, and Time (XYZT), and the majority of LAS implementations support only this data structure. Recent development of LAS has added the ability to access non gridded, 'in-situ', data from a variety of databases. The LAS User Interface has also been enhanced to allow the user to request XYZT subsets and apply additional filters such as Probe type, etc. The primary challenge in providing access to the WOD01 profile data base is one of data access: locating and returning tens of thousands of records from a multi-million record database in a 'reasonable' amount of time (<30 seconds). Once the data is accessed, it is then processed "on-the-fly" by LAS to generate one of many visualization or data products.

This presentation will explore the architecture of the WOD01 LAS database and the reasoning behind it. We will discuss the LAS interface to the database and the back-end visualization application Ferret. Finally, we will report the current status and future plans for the WOD01 LAS.

Supplementary URL: