Exponare 5.1 Administration User Guide - Pitney Bowes Software

Chapter 2: About Exponare Server and Clients
Layers and Features
As mentioned above, a key part of a workspace is the definition of different map Layers. Each Layer
normally represents only one type of information. For example, a map for displaying residential
areas might have separate Layers for properties, roads, sewerage, electricity, water and so on. Each
Layer has a set of Features that represent physical objects or other map data. When working with a
map, the user can select Features from one or more Layers and view information about those
specific Features.
SQL Support Tables
SQL Support Tables are tables of spatial or non-spatial data used in the processing of Data Binds
and Queries. SQL Support Tables can be part of the workspace file, or loaded separately from TAB
Files. Only workspaces and TAB Files can be loaded into a Work Context, but TAB Files can refer to
external database tables if required. Only those tables that are explicitly loaded are available for use
in a Work Context.
Selections and Queries
Exponare offers the ability to work with selected Features on the Layers of a map. Indicating the
Features to work with can be achieved in two separate ways: (1) by using map selection tools, or (2)
by activating Queries. The first method, map selection tools, is the most simple and suffices for most
requirements.
Queries are a more complex (and more powerful) selection method than the visual tools. A Query is
a logical statement that defines the Features that should be selected. For example, a simple Query
might read:
Select all the Avenues in Smallville.
This Query indicates that all of the roads in ‘Smallville’ whose type is ‘Avenue’ should be selected,
regardless of what is currently visible in the map display.
Once a set of Features has been selected, either by map selection tools, or by Queries, two
separate actions occur. The first is that the selected Features are visually defined on the map. For
example, linear Features might by highlighted and area Features shown with a shaded background.
The second is that information related to the selected Features may be displayed. The system for
linking Features to a set of information is called Data Binding.
Running a Query only causes Features to be selected. A Data Bind must be configured for
information to be displayed regarding the selected Features.
Data Binds
Data Binds are links from Feature identifiers to Feature information. Any loaded SQL Support Table
can be used for a Data Bind. For example, on a map containing a set of roads, we may have
information about each of the roads, such as “Name’, “Maintenance schedule’, and “Current
condition’. To set up the Data Bind, each road is given a Feature ID, and a database table is created
that has a primary column of Feature IDs, and associated columns for “Name’, “Maintenance
schedule’, and “Current condition’ and other information. Whenever a set of roads is selected, the
set of Feature IDs is obtained and the database table can be consulted to access the associated
information.
Administration Guide 17