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 (user’s

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 it’s 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

It’s 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