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Software Requirements Specification

General Description

This section of the SRS contains a description of the product and functionality provided by the product, main features of the product, a description of each type of user of the system, constraints on the development team, and factors that affect the requirements stated in the SRS.  In order to describe what the system will do at a high-level Use Case diagrams and Scenarios are used in this section.

Product Perspective

The AVS system will serve as a search engine for remotely sensed data and it will allow scientists and the general public to search over a vast amount of remotely sensed data for sets of information. The system’s search interface will allow the user to specify various characteristics of the data in order to find data sets that match the given search criteria, e.g. spatial resolution, spectral resolution, geographical location, costs. The result of the queries will be links (URLs) to the location of the matching data. This system will also allow its users to provide data sets of their own which, after a validation process, will be supplied to the information repository in order to make it available to other users. This system is self-contained however, it is not independent given that its functionality relies on the database that PACES will provide, which will not be a part of the system.

AVS is a web-based software system that provides services for registered and non-registered users. Registered users, known as data providers, are able to store descriptions of their online remote sensing data sets. These data sets may include “pretty pictures”, geo-referenced images, and binary data. Providers add metadata to the system by providing a link to their data and a specific description of the data, including location, date, data type, longitude, and latitude. Non-registered users, known as visitors, can search and browse through the metadata. To maintain the security and integrity of the metadata, validators verify and data posted by data providers before it is available to visitors.

AVS is being developed for PACES. The technical mission of PACES is to contribute to NASA’s Earth and Science Enterprise by conducting research in several areas of the geological, physical and environmental sciences. Other search engines are available on the World Wide Web (WWW) to search for remotely sensed data however; these search engines are not unified as a common entity. The interfaces for each of these search engines vary, and the information they contain may not be as reliable as needed for scientific purposes. The AVS software system intends to merge all of the most important and dependable remotely sensed data sources into one entity that will provide this information for free to the general public, according to PACES mission statement.

User Characteristics

This section describes the actors of the system and gives a description of features and characteristics that influence the software system.  The use case model consists of actors, use cases and relations among them.  


This section describes all of the users of the system and their different roles and general function in it. An actor is an outside entity that interacts with the proposed system.  When an actor interacts with a system it performs a use case.


This actor is a person who comes to the system to search for remotely sensed data. The visitor is a person who can either have a strong educational level or have no professional background, e.g. a Ph.D. and a high school student, respectively. The visitor may perform two types of search, a simple search by submitting a query to the search engine, or an advanced search, where the user is given a set of descriptions of type of data to be searched.


Software Engineering II

CS 4311 Fall 2004


9/2/2004   4:15 PM



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