City Planning Level
The information system processing is broken down into different levels:
Area
This is the highest level in the breakdown of the enterprise information system. For most companies, there is a data acquisition area, an information processing area, a management area, a repository area, etc.
District
The district groups the processing that can correspond to an activity or a business function, and therefore to a type of information.
Block
The block corresponds to the basic component of the city planning. A block is a homogeneous set of data and processing. Computer applications are grouped within the city planning blocks.
etc.
*Additional levels can be specified if required.
Areas and Sub-Areas
"Sub-areas" can be created from an area, whatever the city planning level ("area", "district" or "block").
In a city plan, when you create a sub-area from an "Area" (right-click the city planning area New > City Planning Sub-Area), the sub-area automatically becomes an area of "District" level.
In a city plan, when you create a Sub-area from a "District", the sub-area automatically becomes a "Block".
*The appearance of the area changes according its city planning level.
Properties of areas, districts and blocks 
To view the City planning level of the area:
*Open the properties dialog box of the area.
The Color attribute brings a further dimension to your city plan diagrams. The value given to this attribute changes the shape color representing the area, district or block displayed in the diagram.
The City Planning tab is used to specify the applications, databases, services, or use cases concerned.
Example of breakdown into areas, districts and blocks 
For this purpose, we will use a fictitious enterprise called "Voyages & Vacations".
The Voyages & Vacations company was originally a sailboat manufacturer.
To sell and rent its sailboats, the company developed a network of offices and travel agencies in tourist destination islands such as the Caribbean Islands and Hawaii, as well as in major cities around the world. It also developed a network of banking offices to finance the purchase of its boats by private parties.
As technology changed, the original activity of boat construction declined, until only the activity of manufacturing spare parts for boats remained.
However, the boat rental and sales activity grew enormously. The company now offers pleasure boat rentals of all sorts, including both sailboats and motorized craft, and related services such as diving equipment rentals, car rentals, hotel reservations, and airline ticketing. It also now has several cruise ships and its own restaurant chain.
The company is organized into three main subsidiaries:
The Voyages & Vacations company, which manages the rental of pleasure or cruise boats and related activities such as hotel reservations and airline ticketing.
The MyBank company, where the banking activities of the group are handled.
The HBC company, which manufactures and sells spare parts for boats.
Here is a detailed list of the various activities of the group:
Boat rentals for boats of all sizes
Airline ticketing and hotel reservations
Car rentals
Organizing cruises
Organizing corporate seminars
Managing technical documentation on boats
Managing boat parts and boat repairs
Purchasing boat parts
Manufacturing and selling boat parts
Managing libraries so books are available to passengers
Managing the ATMs available to passengers on cruise ships
Managing stock orders for passengers on cruise ships
Other banking services
Catering services on-premises or in the home
To contribute to the introduction of new applications into its information system, and to facilitate moving existing applications onto the Internet, the company IS manager began to map a city plan for his information system.
The following diagram shows a functional city planning diagram for this information system.
Functional city planning diagram for the information system
The information system is divided into areas, based on their interactions with the customers and partners of the company.
*The color of the areas, districts, and blocks represents the subsidiary where these areas, districts, and blocks originate: Voyages & Vacations in yellow, HBC in green, and MyBank in blue.