Image Service Use Case

Point Of Contact: Tim Pugh, Aus. BOM

Description

Give a short descriptive name for the use case to serve as a unique identifier.

An image service for a data catalog service

Goal

The goal briefly describes what the user intends to achieve with this use case.

This use case is to describe a "quick-look" data service so an external user or service may receive an image of the data.

Summary

Give a summary of the use case to capture the essence of the use case (no longer than a page). It provides a quick overview and includes the goal and principal actor.

An image service embedded within the Hyrax server would provide an additional service to generate images of specific data sets within an OPeNDAP service, and return compressed images of the data to an external user or service.

Actors

List actors, people or things outside the system that either acts on the system (primary actors) or is acted on by the system (secondary actors). Primary actors are ones that invoke the use case and benefit from the result. Identify sensors, models, portals and relevant data resources. Identify the primary actor and briefly describe role.

A user may request a quick look at a specific data set and indices to receive a compressed image or data array for visual presentation before requesting larger amounts of data.

In addition to the user, an external service such as a data catalog, may request a quick look at a specific data set for visual presentation.

Preconditions

Here we state any assumptions about the state of the system that must be met for the trigger (below) to initiate the use case. Any assumptions about other systems can also be stated here, for example, weather conditions. List all preconditions.

Triggers

Here we describe in detail the event or events that brings about the execution of this use case. Triggers can be external, temporal, or internal. They can be single events or when a set of conditions are met, List all triggers and relationships.

Basic Flow

Often referred to as the primary scenario or course of events. In the basic flow we describe the flow that would be followed if the use case where to follow its main plot from start to end. Error states or alternate states that might be highlighted are not included here. This gives any browser of the document a quick view of how the system will work. Here the flow can be documented as a list, a conversation or as a story.(as much as required)

Alternate Flow

Here we give any alternate flows that might occur. May include flows that involve error conditions. Or flows that fall outside of the basic flow.

Post Conditions

Here we give any conditions that will be true of the state of the system after the use case has been completed.

Activity Diagram

Here a diagram is given to show the flow of events that surrounds the use case. It might be that text is a more useful way of describing the use case. However often a picture speaks a 1000 words.

Notes

There is always some piece of information that is required that has no other place to go. This is the place for that information.

Resources

In order to support the capabilities described in this Use Case, a set of resources must be available and/or configured. These resources include data and services, and the systems that offer them. This section will call out examples of these resources.

Other Resources

Resource	Owner	Description	Availability	Source System
name	Organization that owns/ manages resource	Short description of the resource	How often the resource is available	Name of system which provides resource