From OPeNDAP Documentation

Point Of Contact: James or Nathan

1 Description

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


2 Goal

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

Find data to use with ASPECT

3 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.

Search for a data file, served by BALTO, using Google.

4 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.

  • Google general search web site
  • BALTO broker site (a specific instance of Hyrax)
  • Data provider - the person who puts the data file on BALTO or who configures BALTO so that it can access the data if it's 'served' by some other source on the Internet.
  • Data user - person who searches for data

5 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.

  • The data are either:
  1. served by BALTO, or
  2. BALTO can broker requests to the server that holds/serves these data
  • Google has indexed BALTO and that index operation has included the data it can access using its brokering capabilities

Note that using the remote data is a separate use case.

6 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.

The Data user decides they want to use data set X and search for it.

7 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)

  1. The Data user goes to Google and enters text they hope will find the data set
  2. Google returns a page of links
  3. The Data user copies the one that seems like it 'is from BALTO' and pastes it into an application (e.g., ASPECT)

8 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.

  1. The Data user doesn't find any BALTO link but does find a link that looks like it references something BALTO could broker.
  2. The Data user finds nothing useful.
    1. Stop; fail

9 Post Conditions

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

  1. Normal flow: Data set URL found
  2. Alternate flow: Data set URL not found
  3. Alternate flow: Data set URL found, but it's not currently accessible using BALTO. BALTO might be able to broker it, but it will have to be added to broker. See BALTO:ADD_BROKERED_DATA

10 Activity Diagram

Here a diagram is given to show the flow of events that surrounds the use case.

11 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.

  1. Should we include cases where Google Dataset Search is used instead of the regular Google search?
  2. Should we include cases where some kind of local Balto site search is used?

12 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.

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
BALTO OPeNDAP, then...? An instance of Hyrax, configured to broker specific datasets served from other network locations 24/7 AWS (who pays in the long term?)
Google search Google I think we know what this does 24/7 Capitalism