ABSTRACT: PROBLEM: The challenge facing our Department was to get GIS enterprise tools and data to our 1600 users at a very low cost. STRATEGY We created a front-end interface known as the DEI (Data Extraction Interface) using Sylvan OCX tools,MapObjects, in-house Visual Basic code, AML, and ArcView 1.0/3.0. The DEI can be thought of as a fat client/fat host environment with GUI and ArcView/ArcExplorer on the client, and extraction and compression on the host. ArcView/ArcExplorer as the standard interface was used due to ease of training, simplicity of use, and because some of the software is free over the Internet.

PROBLEM DEFINITION

Jefferson County has 2500 employees, 1600 of whom have PCs. The challenge facing the GIS (Geographic Information Systems) Department was to get GIS tools and data into the hands of these users. Additional challenges included the need for very low cost per seat, laptop access, very large datasets, training issues, and the users having little knowledge of GIS.

Carefully collected over many years was an enormous amount of information about Jefferson County. The problem was that this information was usable to only a handful of highly trained GIS specialists. Anyone in the organization needing reports from this data had to make a request and wait until time was available for someone to provide the needed items.

The difficulty was to deploy tools organization-wide that would allow users quick and easy access to the GIS data without the need for extensive training.

Thus was born the concepts of the Data Extraction Interface (DEI) an easy-to-use tool that can extract any data. Basic display, query, analysis, and mapping capability is available to all through the DEI. Over 50 gigabytes of data are available in the form of over 45 discrete layers. These layers include roads, aerial images, parcels, land use, hazards, natural resources, political boundaries, businesses, utilities etc.

STRATEGY
Essentially, the question was, "How does Jefferson County most efficiently and effectively implement enterprise GIS " Traditionally, the implementation of enterprise GIS using ArcView has two approaches:

A true enterprise solution for the first approach would have one license available on the LAN for each user who might request it. In reality, a certain number of licenses would be made available on the LAN to cover the demand (or some percentage of the perceived demand) for some moment in time. This assumes that not everyone needs access to ArcView at any one time. This has the obvious advantage of minimizing the number of licenses that need to be purchased. Disadvantages are that not everyone may use GIS functionality concurrently, and that network limitations can adversely affect performance. To date, the simultaneous utilization of graphics-intensive software packages such as ArcView on a LAN is impractical when more than just a few sessions are running on the network.

The second approach moves the GIS software to the user's PC, and uses the LAN for bulk data transfer. Provided the user's PC is optimized for using memory and graphics intensive applications such as ArcView, performance on the client-side is good. The disadvantage of this scenario is cost. A license for the product must be bought for each PC on which it will run. So while network-driven computing is prevalent in current technical literature, it is, at this time, not economically feasible to deploy applications such as ArcView on a network on an organizational-wide basis.

Enterprise GIS with ArcView requires ArcView to run from the user's PC. Thus, the total cost of ownership of a GIS becomes the real issue concerning enterprise GIS. Volume-buying lowers the cost of licensing products such as ArcView 3.0 considerably. But volume-buying still leaves the cost at several hundred dollars per license. When 1600 users are considered, this cost becomes prohibitive. At Jefferson County, while we were running Windows 3.11, we assumed that most of the county GIS users require only basic display, query, analysis, and mapping tools. ArcView 1.0 meets this need, and it is freely distributed. Another excellent reason for using ArcView 1.0 is the ease of training and simplicity of use. A much smaller portion of the county's GIS users, including GIS Department staff, Assessor's appraisers and mapping staff, some Planning Department staff, etc, would require the robust relational and analysis tools which could be met by ArcView 3.0. The expected results of this strategy would have the following effect:
Accelerate the rate of GIS implementation.
Eliminate incremental deployment of GIS in favor of organizational-wide GIS access.
Dramatically cut the cost of enterprise GIS technologies.

The DEI was made operational in November of 1996. Jefferson County is currently migrating from Windows 3.11 to Windows NT in the desktop environment. This evolution has necessitated a change in our enterprise GIS solution. Pandora is the Windows NT evolution of the DEI enterprise GIS solution. The migration to NT is expected to last into the second half of 2000, so we expect to maintain the DEI until that time. We could have merely updated the DEI to run on NT (which we did do) but the change gave us a chance to reevaluate the entire application strategy. The DEI is a client/server application which takes 3-5 minutes to deliver data to the client ArcView application. We wanted a significantly faster application in which the retrieval component (DEI) and viewer component (ArcView) were one application. Like the DEI and ArcView 1.0 it would be easy to use, but it would display data in a 30 second time frame. After initial testing it was decided that Pandora would maintain the DEI's client/server approach, but would also have a component consisting of Internet browser technology.

Pandora versus the DEI Similarities and Differences

The DEI, our current client-server application, uses Environmental Systems Research Institute's (Esris) freeware ArcView 1.0 as a cornerstone for deploying basic GIS functionality on the desktop. Any County employees with Windows 3.11-based PCs connected to the County's LAN may run the DEI with ArcView 1.0 providing GIS functions. Note that the DEI also serves the 100 or so County employees who have licensed the more robust capabilities of ArcView 3.0. Pandora likewise will support users who have upgraded their ArcView software.

The DEI allows the user to specify the desired data themes for the desired extent (area) of the county and extracts this data from the County's data warehouse. The DEI then FTPs the data to the desktop and fires up ArcView 1.0 (or 3.0, if installed), displaying the data using default symbology. All of ArcView's basic display, analysis, and mapping capabilities are available to the user at this point.

Since Windows NT is a 32-bit operating system, and ArcView 1.0 is a 16 bit application, Pandora needs a replacement for the ArcView 1.0 portion of the client-side.

The most obvious replacement for ArcView 1.0 as a client-side GIS driver in a 32-bit environment is Esri's ArcExplorer, which is also freeware. ArcExplorer was built with Esri's MapObjects and Visual Basic expressly for Windows NT. Unfortunately, ArcExplorer doesn't contain all the basic GIS capabilities that ArcView 1.0 did.

Since DEI users are accustomed to ArcView 1.0's capabilities, Pandora's Windows NT functionality must meet or exceed Windows 3.11 levels. To accomplish this, we've decided to use MapObjects with the ArcExplorer source code as the foundation for GIS on the client side. MapObjects is a suite of GIS tools developed for Windows NT environments. It represents the componentization of ArcInfo, Esri's flagship professional GIS software. Visual Basic version 4.0 was used as the front-end and driver for the DEI. Pandora will use Visual Basic 5.0 to drive the application. Visual Basic and toolsets like Delphi and PowerBuilder are the standard means for working with MapObjects.

Pandora represents a significant departure from the DEI design by eliminating Arc Macro Language (AML) from the host side processing. Pandora utilizes Esri'S Spatial Database Engine (SDE), sitting on top of the Informix relational database management system (RDBMS), to serve data to the client. ArcInfo is fast at delivering data, but SDE is designed for delivering data very fast- especially when very large datasets are involved, such as parcel data, containing millions of polygons.

Our initial approach to enterprise GIS was to build a client-server application using ArcView 3.0/Avenue for the prototype. The prototype evaluation did prove to be too slow and too costly. However, the concept was workable. We created the DEI using Sylvan OCX tools, in-house Visual Basic code, AML (Arc Macro Language), and ArcView 1.0/3.0. The application works by allowing the user to select where (on a map with box or by an address) and then what data layers by use of a single screen GUI. The area of interest and data layers requested are then sent to the host where a clip engine cuts out the window of the area of interest for each of the data layers selected. The resultant data files are then zipped and sent by FTP to the client.

The DEI is a client-server approach to enterprise-wide distribution of GIS at the desktop level. Clients are users on a local area network (LAN) who request services or resources from a server, which then performs the requested processing. Visual Basic and ArcView 1.0/3.0 form the client side of the DEI, while ArcInfo and Arc Macro Language (AML) drive the server side.

In function, the DEI can be thought of as a fat client/fat host environment with the GUI and ArcView on the client, and the extraction and compression on the host. The DEI allows the user to select the data themes (layers) of interest for the desired portion (area) of the county, extracts the requested information from the county's data warehouse, delivers the data to the user's PC, and then loads the data as a "project" into ArcView. Both the client and server sides of the DEI have been designed for speed and performance. Large requests may be processed in a few minutes, depending on the number of jobs in the request queue. While Visual Basic drives the DEI, GIS functionality is contained in ArcView, the other component of the client-side application.

Pandora uses a conceptually simpler approach. Like the DEI the user select the data themes and area of interest. However, Pandora is purely a client side application, which can request data directly from the SDE. The resulting SDE data is the "rendered" by Pandora to produce a graphical display. Pandora is optimized for speed. It will never contain all the features of ArcView 3.0 but it will become a modular foundation for future custom MO applications requested by our customers.

The Data Extraction Interface (DEI) is a client-server application. Visual Basic takes user input, requests spatial data from ArcInfo running on a UNIX server, and takes the resultant output from the server and loads it into ArcView. ArcView 1.0 contains basic display, query, analysis, and mapping capabilities. ArcView 1.0 was enhanced with Esri authorization by altering the binary .av file into an editable .apr equivalent file. This allows for the creation of standard user-friendly legends. Version 3.0 of ArcView was vastly improved in terms of functionality. It contains even more features of Esri's ArcInfo, including functionality for editing geometry and improved mapping. Consequently, Esri has released ArcView 1.0 as freeware and has made it available to the world from their home page on the World Wide Web. The DEI works as follows:

The client-side of the DEI is driven by programming code written in Visual Basic. Visual Basic is an object-oriented toolbox containing powerful programming resources, such as tools for utilizing Object Linking and Embedding (OLE) technology. Visual Basic was also used to build the menus (forms) which constitute the front-end for the DEI. ArcView 1.0/3.0 GIS functionality is contained in the second component of the client-side of the DEI- ArcView. Depending upon what is installed on the user's PC, either ArcView 1.0 or ArcView 3.0 is fired up by the DEI once the data requested by the user has been delivered to that PC.

The server side of the DEI uses ArcInfo (rev 7.0.4). An ArcInfo session which constantly runs on a UNIX server forms the server-side of the DEI. This session is spawned at boot time once the license manager for ArcInfo is brought online, and it executes a program written in Arc Macro Language (AML). This AML continuously looks for DEI requests to process. A loop in the program either starts needed geo-processing when the request arrives on the server side, or puts the process to sleep for 10 seconds before checking again. Depending upon the timing of requests arriving from the client-side, jobs may form a queue in which the server processes data on a first-come, first-served basis. Upon completion of a job on the server side a flag is set. The client side, which has been waiting for this signal, then finishes the process of transferring data back to the users PC and loading the "project" into ArcView.

A critical factor in the success of the DEI was a high-speed network. Fortunately, the Network Services department had been working for some time to implement the Jefferson County Information Network (JCIN), a high-bandwidth network with switched ethernet segments and in high-traffic areas, switched ports. Fiber optic cable is extensively used to connect the backbone and all of the buildings on the County's campus together, and high-speed Frame Relay is used to connect remote buildings into the network.

The performance problems of executing ArcView from a local area network (LAN) require both the DEI's Visual Basic components and ArcView 1.0/3.0 to reside on the user's personal computer (PC). Initially, users needing GIS functionality access the DEI through an option available on the LAN. Pressing the appropriate button in Windows 3.11 on the LAN causes the DEI's Visual Basic components to be installed, and, if necessary, installs ArcView 1.0. This is the usual scenario since the majority of the county's GIS community use the freeware version of ArcView. Those users requiring the extended capabilities of ArcView 3.0 have this software pre-installed by GIS staff.

Pandora is also client-server application. Visual Basic/Map Objects takes user input, then requests spatial data from SDE running on a UNIX server, and takes the resultant output from the server renders the data and displays it. Pandora contains all basic display, query, analysis, and mapping capabilities of ArcExplorer plus the ability to perform graphical selects and full table display. ArcExplorer source code was enhanced with Esri authorization. The source code was purchased under a separate developer license. This code was then altered by Visual Basic and Map Objects code to create the Pandora application. Pandora works as follows:

Another feature of direct linking to SDE is the ability of the user "pan" their selected window of data. Unlike the DEI where the user was required to re-extract data beyond the initial selection parameters, Pandora allow full interactive panning.

We believe the advantages of a Visual Basic/MapObjects approach to Pandora vastly outweigh the disadvantages.

Future plans include the migration of the Pandora Project to Internet browser technology so that users outside the county can access the functions of the software.

Our total cost of development for the DEI application was about $14,000 using in-house staff. Thus the application was made available to all 1600 PC s at a cost of less than $10/seat. The total costs of the Pandora Project are not known at the time of this writing.

The change the DEI/Pandora has made to the county has been very significant. Users can now easily access the data they need for important decisions in a matter of minutes. Commissioners can easily determine who will be affected by major projects. Planners, engineers and managers can quickly design corridors, which minimize impacts and lower cost. The system has been so successful that it will soon be made available to the citizens and the business community at department front counters, libraries and in a few months, on the Internet. To our knowledge this application is completely unique in that it places GIS functionality on every desktop in the organization with the easy-to-use tools to get just the right data to the desktop.

The DEI and Pandora Project are a software project internal to the GIS Department. The following is a listing of the people who were involved in this effort: