on the data set itself is provided in three windows.
Therefore, if detailed information on a data set is
requested (i.e., selecting Dataset at “Retrieve
info:” in figure 3), one window only is first dis-
played. The user can access the other information
by selecting one of the two buttons labeled Other
Info and Storage Info.
If the information say, about the owner or contact
person (see figures 4 and 5) is displayed, and a new
data set is selected from the list in figure 3, request-
ing Retrieve with Contact and Owner still enabled,
will cause the already displayed windows to be
updated with the information on the new data set.
3.4 Visual Queries
Visual queries involve first invoking a display of a
globe, and then determining a region or an area of a
globe where information is desired. A user can
invoke this facility of MetaView/GIS by opening
the map database. The button marked “Spatial
Browser” pops up the map window. In this win-
dow a user can display any region of choice. Using
a mouse and a rubber banding selection technique,
a user may zoom in on an area to facilitate more
precise region selection. The selected area is inter-
preted as the bounding coordinates and is transmit-
ted to the “Search region:” in the Database
Information Window. A user can also specify the
search region manually for searches to be con-
straint within the region. The provision of visual
spatial querying capability is one of the main dis-
tinguishing features of MetaView/GIS.
3.5 Getting Help
Each window of the MetaView/GIS interface has a
help button. In addition most buttons, in display
text areas or labels have individual help messages
associated with them. These messages appear
when the buttons are mapped (i.e., when the cursor
enters the boundary of the button). These help mes-
sages appear at the help message string in the upper
part of most windows. For example, in fi gure 6, the
text "Scroll the text information upwards" is the
message string of the Pg-Up button. The message
will be undisplayed if the cursor moves away from
the Pg-Up button. MetaView/GIS help is organized
in an index/contents format. When the help button
of a window is clicked, the help window pops up,
with the required window's index entry and con-
tents shown as the default. While the help window
is displayed, a user can assess other help informa-
tion by selecting the appropriate index entry. The
help window is shown in figure 6 with MetaView/
GIS mailtool’s help contents displayed.
3.6 Update Functions
There are essentially, two classes of users of Meta-
View/GIS. A general public user and a privileged
user. The privileged clients are the database owners
that provide the metadata of their databases/data
sets to the MetaView/GIS database. These database
vendors (i.e., owners of databases or the data sets)
need to insert data in MetaView/GIS database and
also update existing information. MetaView/GIS
provide a more flexible approach and friendly
entry forms for these purposes. To insert a new data
or modify an existing information, such privileged
users must pass a password validation check. All
database vendors have password that allows them
to gain access to the MetaView/GIS update func-
tions.
To modify information (say a contact person's
data) on a particular data set, that data set must be
selected from the "Search Result:" list in the
Database Information window. Selecting of the
Update/Modify option from the pull-down menu
pops up the Update windows Header window as
shown in figure 7. The user must then enter a valid
password and then select the data to be modified.
For example, if the user clicks on the Person but-
ton, this pops up a window with the current data
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