An exemplar GUI (Graphical User-Interface) layout and its components shown in FIG. 6a is designed to organize information from an extensive, complex data set.

The special control apparatus maximize ease in retrieving subsets from the database.  The navigation to the desired map can be accomplished via an optional index, 1-4, on the left by clicking on bar segments and list items. Retrieval Bar, 1, for switching categories of mapsets and Retrieval Bar, 2, for switching subcategories of mapsets call forth clickable lists of mapsets, 3, within the selected category and subcategory. The example shows a list organized in alphabetical order.  Retrieval Bar, 4, is used for calling forth additional list information.  The hilited segment designates the portion of the list that is displayed; clicking another letter calls up the portion of the list starting with that letter.  Clicking on a map name in the list brings its base map into the Map Area.  Orientation and navigation within a set of maps is accomplished via the Context Map, 5 in lower right, which shows the location of the present map within the next higher level map. Clicking outside its toned area, calls forth the next higher level map (zoom-out).  Zoom-in capabilities, 5a, are provided via a key-accessed layer showing clickable zoom-in areas on the main map.  Clicking on the "Home" icon, 6 upper right, retrieves the top-level map of the mapset.  

Upon retrieving the desired mapset with its basemap visible in the Map Area, the user may click on the Topic Selector, 7, to retrieve site or object information for a particular topic in several ways.  Clicking the underlined topic name will replace the base key with a topic-related key.  Clicking on the box to the left of the topic name will call forth a query box in the key or as a pop-up (see FIG. 6b).  Clicking on the down arrowhead will replace the topic list with a list of subtopics.  The retrieval bar above the list shows the number of levels of topics and subtopics including and above the current subtopics list; clicking a segment will return to the higher-level topics list.  Clickable keys are used to show and hide overlays to the basemap in the Map Area.  The key, 8, shows a set of symbols; when a symbol is clicked, the software calls to the database to show all that type of site or object positioned properly on the map.  Keys for additional types of site or object are accessed by clicking on the "next" and "back" arrowheads at upper right of key, 8a.