Digital Earth: TerraVision: User Guide


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Digital Earth > Terravision^TM > User Guide > Tcl/Tk > OAA Menu

The OAA Menu

The Open Agent Architecture (OAA) is a framework for integrating a community of heterogeneous software agents in a distributed environment. TerraVision can be an OAA agent, which means that it can connect to an OAA "facilitator" and can then be manipulated by any other agent. This provides the capability to communicate between, and to control, remote TerraVision clients. For more information on the OAA, refer to http://www.ai.sri.com/~oaa/.

Connect

In order to interact with other OAA agents, TerraVision must first connect to an OAA facilitator. This is a server that can be running on the local machine, or a remote host over the Internet. In order to connect to a facilitator, you must specify the hostname and the port number that it is running on. TerraVision also allows you to specify an ID string for your TerraVision viewer - this ID can be used to send OAA messages to your specific viewer.

You can download an OAA facilitator for your machine from the OAA web site.

List Viewers

It is often useful to know what other TerraVision viewers are connected to the same facilitator as you. This can be useful for example to find the ID string of a TerraVision client that you wish to send a message to. The List Viewers dialog shows you all TerraVision (5.1 or higher) clients that are currently connected. For each of these, it will tell you the ID string of that client, the host that it is running on, the operating system and architecture on that host, and the number of cpus. New TerraVision clients may connect to the facilitator over time, or others may disconnect, you can therefore update the list at any time by clicking on the "Refresh" button.

Send Message

You can send text messages to other TerraVision clients that are connected to the same facilitator as you. These messages appear on the status bar of the TerraVision viewer. Simply type in your message into the text area, and click on the "Send Message" button.

You can either send messages to yourself, to all other TerraVision clients, or to specific TerraVision clients. You control the target of your messages with the "Send to:" field, for example.

all = send the message to all connected TerraVision clients
self = send the message to yourself (do not need to be connected to a facilitator)
id('ID1'),id('ID2') = send the message to 2 specific clients only

Send Command

As well as sending simple text messages to other TerraVision OAA clients, you can send commands to control the navigation, and display of those clients. TerraVision supports a number of commands that any OAA client can send to it. This dialog simply provides an interface to this capability. You can specify the TerraVision command in the "Command:" field and then click on the "Send" button to send the command.

The OAA Interface section of this user manual describes all of the currently supported OAA commands. In the example below, we show how you can tell all connected TerraVision clients to render in wireframe mode. The text box at the bottom of the dialog displays the result of the OAA query in the native Prolog syntax.

As in the Send Message dialog, you can either send messages to yourself, to all other TerraVision clients, or to specific TerraVision clients. You control the target of your messages with the "Option(s):" field. In addition, the options field can also be used to specify any optional arguments for the specific command being sent.

all = send the message to all connected TerraVision clients
self = send the message to yourself (do not need to be connected to a facilitator)
id('ID1'),noanim = send the message to a specific client with the "noanim" option specified