[an error occurred while processing this directive][an error occurred while processing this directive]
The City of Los Angeles Implements Its New Web-Based Zoning Information and Map Access System
The City of Los Angeles Department of City Planning (DCP) is responsible for all of the land use and zoning in the City. For more than 70 years, the zoning and land use data was recorded and stored on 1,888 paper maps that were used to provide information at public counters.
In 1997, Esri's Professional Services Division began working with DCP to develop a comprehensive and sophisticated zoning information system. The goals of the project were to automate manual mapping processes; reduce redundancy of effort; improve the quality, consistency, and reliability of the geographic data; provide access to the data from many locations; and increase productivity and customer service. This enormous effort was divided into two major projects--(1) data conversion and application and (2) database design--which resulted in the development of the Zone Map Automation (ZMA) system.
ZMA is a GIS-based, parcel-level zoning information and analysis application that provides City users with access to zoning data using either a Web browser or a PC client-executable application. The first part of this multiphased project focused on developing the core (Web) and the extended (PC-executable) functionality to meet the requirements of the City. The core functionality of the ZMA application provides an easy-to-use, Web-based data access and display system. This system allows a user with a browser to find a property and view the applicable zoning information over the Intranet. The extended functionality of the system was built on the core functionality to provide more advanced queries and high-quality map output. Additional phases of the ZMA project are ongoing and will provide additional functionality to the system. Some of the queries available are by property address, nearest intersection, map book-page-parcel, legal description, community map, and map sheet.
Esri and its subcontractors comprised one of three teams that performed the data conversion for DCP. This was originally proposed as a four-year effort to automate the 1,888 hard-copy zoning maps. Now, however, due to good project management, the project is ahead of schedule. Data entry was performed through an editor developed by Esri. Programmatic database verification and quality assurance were performed through Esri's QCView software.
Application and Database Design
The application development strategy was first to build a core tool for deployment to Web browsers and then to extend that tool to provide additional functionality with the PC-executable version. The ZMA user interface is called the Zoning Information and Map Access System (ZIMAS).
"The underlying rationale for this design model was to deliver ZIMAS as a unified set of component software tools that could be more readily maintained by the City because they were built with industry-standard open technology," says Jordan Henk, Esri's first phase project manager. "This means (1) that as new versions of the component technology are released, ZIMAS can be accordingly upgraded, and (2) that the ZIMAS application can be maintained and enhanced by the City's programming staff as needed."
To meet the requirements of DCP and to provide an efficient development environment, Esri built the ZIMAS application with Microsoft's Visual Basic and Esri's MapObjects to work with Esri's ArcExplorer. Consequently, the application is ActiveX compliant. The use of component object model (COM)-compliant technology should provide the City greater options for extending and enhancing the ZIMAS application over time.
The ZMA database design effort included the design and implementation of two databases that reflected DCP's organizational framework and provided user functionality and operational efficiency. ArcInfo LIBRARIAN will be the operation or transactional database in which data is maintained and all data editing is performed. Spatial Database Engine (SDE) and Oracle were used to create an extensive, seamless publication database that was essentially a mirror image of the operation database with the addition of a few critical tables and relations.
System Architecture and Extensibility
ZIMAS is an integration of many technologies including Microsoft's ActiveX, Internet Information Server (IIS), Internet Explorer, and COM; Oracle's enterprise server and clients; and Esri's MapObjects, ArcExplorer, MapObjects Internet Map Server (IMS), and SDE. At design time, Esri had two options for ZIMAS. One option was to develop a UNIX-based server operation (GISData Server). While this scenario was consistent with the volume of data to be published, Esri chose the option to extend the ArcExplorer client and server applications with MapObjects and . The design and development for the Web version could then be leveraged to produce an executable desktop application.
Desktop Mapping and State Management
One of the significant challenges with ZIMAS was to provide high-quality mapping over the City's Intranet. With a simple Web-based mapping application, each user must use the same map layout for his or her area of interest. With ZIMAS, users can choose layer visibility, which requires the client application to pass its state to the server. This compounds the complexity of the server, which must adjust its data query and rendering for each client request. Although the server does not actively manage the state of each connected client, it is designed to produce custom maps for each user request.
All Internet applications are handicapped by low bandwidth bottlenecks and service queuing at the Web server. With ZIMAS and , good performance is also affected by data access (I/O), data intensity, and number of requests per server. Using , the administrator is able to tune both the number of servers running and the number of connections per service. This allows the administrator to balance request volume with Web server processing capability. The sheer volume of annotation data for the zoning and land base layers challenged the success of ZIMAS. Rendering, however, provides several options for annotation with MapObjects-based ArcExplorer including scale-based display. The administrator is able to adjust the threshold scale at which annotation layers are included in the map. In addition, the administrator is able to use SDE to refine the spatial indexing for annotation features and so tune performance accordingly.
ZMA is already being used by hundreds of City employees in many departments. The application has simplified work at the public counters by providing accurate zoning data quickly and reliably.
"We anticipate that ZMA will soon be expanded to the Internet. Then anyone will be able to perform basic research on properties from home or office computers, eliminating the need to travel to a City facility, pay for parking, and stand in line to get the same information. This project has streamlined our operations and provided real services to the public as well as to City employees," says Madeleine Rackley, DCP project manager for ZMA.
For more information, contact Madeleine Rackley, DCP (tel.: 213-580-1373, E-mail: firstname.lastname@example.org) or Bill Bayham, Esri project manager (tel.: 909-793-2853, ext. 1-1246; E-mail: email@example.com).