Using DBView
A typical DBView user scenario would be to define a geographic area, select
the desired map-information layers and map features to be displayed, and
then utilize the provided GIS tools and extensions to analyze the available
temporal and spatial data. The functional components of the Tools,
Extensions and Pan/Zoom options of DBView are
offered in pulldown menus from the toolbar (fig.
1).
Defining the Geographic
Area
The Pan/Zoom options, included on the main pulldown menu
bar, offer the user a number of ways to define and display a geographic
area of particular interest. Zoom-in options permit the user to
magnify an area of interest by 1) defining a rectangle on the screen using
the mouse, 2) keying in latitude/longitude coordinates, 3) specifying cover
features, 4) identifying a particular 1:24,000-scale topographic quadrangle
map, and 5) selecting data-collection sites. Three pre-defined zoom-out
options enlarge both x and y dimensions of the currently displayed region
by 10, 30, or 80 thousand meters or feet, depending on the units of the map
projection. A fourth zoom-out option allows the user to specify the
enlarging dimensions using units of their choice of feet, meters, or miles.
The Pan option provides the ability to display the region adjacent to the
one currently displayed. A Previous option permits the user to re-display
the area that was previously displayed. This enables the user to readily
zoom in and then zoom back to the original area with ease.
DBView Tools and Extensions
DBView consists of several general purpose tools and extensions that
automate specific GIS functions to help users compile, analyze, and
interpret their data. These tools allow the user to find, display, and
identify mapped features by listing their attributes. Most menu tools
within DBView contain a Help option that briefly describes how to
use the menu and what the tool expects as input. The
Tools and Extensions options, also
located on the main pulldown menu bar, contain the
following:
Identify Menu - provides the capability to point and click
on a displayed map feature and have DBView present the feature's attributes
in either a popup window or as annotation in the map-graphic area,
depending on the identification presentation option (List or Annotate)
selected by the user.