The purpose of Vista (VISualization Tool and Analyzer) is to provide data
retrieval, management,manipulation and visualization. The overall
philosophy is to give a tool to access, manipulate and visualize data
with ease. A graphical user interface is provided for first time and
occasional users. A scripting language will be provided for power users
to automate batch production.
retrieval is accomplished using a two-tier client server architecture.
The data resides on a server and the bulk of the application resides on
the client. The server can serve data both locally and over the network.
Data management is accomplished using the
concept of data reference. A data reference is the reference to the
location of the data set and its characteristics. For instance, a time
series data is referred to by a server address, filename, pathname, time
window and a time interval. Some data references do not refer to actual
data but refer to the set of data references and the operations to be
performed on them to construct the data set. This provides transparency
to the user. For the user there is no difference between such virtual
data sets and the actual data sets.
references can be aggregated in to a Group The default view on a
database file is a Group. Furthermore, one or more Groups form a
Session. A Session can be saved and loaded from a file once created. The
initial Session is created by opening a connection to some server and
directory. The directory of database files then becomes a Session and
each file becomes a Group containing data references.
Data Manipulation is done by creating virtual data
references which contain the set of data references and the operations
to be performed on them. The actual operations on the data are performed
only when the data for the reference is requested. Math operation such
as division, multiplication, addition and subtraction are available
between data sets. Period average and moving average, and merging are
data references which are some other examples of manipulations on data
Data Visualization is done via two
dimensional plots. Examples of such plots are time series plots and
scatter plots. Zooming in and out and paging while zooming are some of
the tools that are currently available. Printing is available in gif and
postscript format. User has complete control of the attributes of each
element in the graph. For instance the user can change the text, font,
size, color and background color of the title. Most of these attributes
can be saved to a file and applied to subsequent plots. Data can also be
displayed and manipulated in tabular format.
A graphical user interface is used to display a group of
data references. The GUI is a view onto the application and contains no
information about the application other than the way the application
desires to be displayed. This separation enables support of undo/redo
commands and the recording of macros which can then be replayed on
Scripting is an
efficient way of accomplishing repetitive tasks. Scripting will use the
same application as the GUI and could use some of the GUI components as