Digital Earth: TerraVision: User Guide


Topics
•	Getting Started
•	Cmd Line Opts
•	Tcl/Tk Version
•	X/Motif Version
	• File Menu
	• Views Menu
	• Logging Menu
	• Prefs Menu
	• Help Menu
•	NS Plugin Version
•	ActiveX Version
•	Configuration
•	Creating Data
•	OAA Interface

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Digital Earth > Terravision^TM > User Guide > X/Motif > "Prefs" Menu

The "Prefs" Menu

The Prefs menu from the main TerraVision^TM window is used to control various global preference settings for the application. Currently this menu has only one entry, for controlling DPSS settings.

DPSS Preferences

The DPSS Preferences dialog lets you set various global characteristics of TerraVision's interaction with DPSS (Distributed Parallel Server Systems). The current options include:

Full DPSS server reads : this option controls TerraVision's behaviour when it is request to re-reads a DPSS server via the "File/Open Dataset/Options" dialog. By default, TerraVision^TM will perform an incremental read, i.e. when it contacts the DPSS server it will only ask for information about datasets that are new from the last time that it contacted that server. If this option is checked, then TerraVision^TM will perform a full server read, i.e. it will find the list of all datasets on the server and ask for information about each one of those (which will take more time).
Request Delay (secs) : TerraVision^TM sends a request list of all the tiles that it needs to the DPSS master. This value specifies the time between sending successive request lists. Smaller values mean tile requests are sent to the master more often, and so you are more likely to get the tiles you need sooner; however, if you send too many requests too fast then you can swamp the master so that it never has time to respond to your requests. The default value of 0.3 seconds seems to give a good trade-off.