Remote Visualisation System (RVS) By: Anil Chandra

Visualisation Requirements Obtain image data residing on different machines at remote locations. Visualise the images – whole images or subsets of larger images. Ability to interact with (analyse) visual data Allow overlaying of catalogue information Provide services at a satisfactory speed

Current Model 1 1.User requests an image/data from a particular service. 2.User receives a rendered raster image (e.g. gif) or FITS image. 3.User visualises downloaded image on local computer. User Database/Catalogue of images Data query Image

Current Models (cont) The current model is an example of client side visualisation. - All processing is done on the client (users computer).

What is RVS? RVS Server User Database/Catalogue of images User command Image + metadata Data request Raw image data A distributed software system that allows scientists to view and analyse astronomical data that are stored in remote locations. A server-side visualisation system

Client User Interface Web browser or standalone application

RVS Server Most processing occurs on the RVS server, not on the client computer. Obtains and stores images from archives/databases Processes images based on user commands Uses AIPS++ Display Library (but not restricted to) Provides its service via SOAP

RVS Server Design Distributed architecture (via CORBA) - Scalability - Performance - Extensibility Web Server Security Service Data Centre Manager Data Storage AIPS++ Client Request

Client – Server Communication SOAP Interface to clients - Standard and popular protocol for web services - Allows custom clients - Based on XML, so its programming language and platform independent

Why Server-Side Visualisation? More processing power on servers than on the average client PC Servers can hold larger images than the average PC due to more memory and storage space Servers can receive larger images faster via higher bandwidth connections to data centres Any time, any where access

Server-Side Visualisation (cont) Software maintenance/upgrades transparent to users Only the server needs to be upgraded, not all the clients. Existing tools such as AIPS++ can be utilised (no need to install on clients) Supports concurrent users access to same session

Disadvantages of Server-Side Visualisation Difficult to design/implement Slower interactivity Poorer performance with smaller size data that require little processing High reliance on server availability/integrity.

The VO Context RVS is a visualisation tool amongst the many tools in the VO. RVS may be used: - By end users to view and analyse images - In conjunction with other services (such as data mining) - By data centres to provide a visualisation interface to their data Its based on a more generic framework that may be used bring other services, besides visualisation, online.

Project Status High Level Design complete A simple prototype (proof of concept) is in progress. - To be completed by 28 Nov 03 Project completion date: 25 May 04 - A complete RVS Server - A demonstration client