A Nationwide WWW-based GIS For Coordinating Community Development Activities

Jim Meyer and Chris Fulcher

Abstract

This paper describes a prototype application that demonstrates the feasibility of using WWW based GIS and a distributed data entry approach to capture local-level or tacit knowledge in its spatial context to address issues or problems of national scope. Like many organizations, 4-H has national priorities that require the collection of information from their local chapters for implementation. We developed a prototype WWW based GIS application that collects geo-referenced point locations and associated surveys of Internet use and availability to address the "digital divide" issue of the penetration and availability of the Internet in communities throughout the United States. The survey results and spatial data are collected via a web-browser in a central database that allows for querying and reporting so that decision makers can understand trends and spatial variations across the country to construct policies that further their goals.

Background

This paper describes a prototype WWW application developed for the 2000 4-H National Tech Conference held in College Park, Maryland from July 8 - 12, 2000. The organizers of the conference asked the Center for Agricultural, Resource and Environmental Systems (CARES) at the University of Missouri - Columbia to build an interactive WWW-based GIS application for the conference participants. The objectives of the application were as follows:

1. Allow 4-H members to locate their local organization's headquarters on a national map, similar to the push-pin maps seen at many national conferences but using WWW technology.

2. Present each user with a survey tailored by the conference organizing committee to gather information on internet access issues in each community represented at the conference. Use the WWW front-end to populate a database with responses that the committee could analyze statistically and spatially.

3. Demonstrate the capabilities of WWW-based GIS and interactive mapping in general to an audience that may not be familiar with GIS.

The authors view this application as a prototype that demonstrates how WWW-based GIS can be used as a tool for addressing community development issues. Often, when an issue of national or international scope is addressed, it is discovered that much of the relevant information is only known or held at the local level. The sheer volume of data describing relevant local conditions in thousands of communities distributed across the entire nation can be staggering. Much of this critical information describing local conditions is perishable. The volume of information collected and the necessity to construct a time-sensitive snapshot of conditions across a wide area makes a centralized data entry approach impractical. Locally-based knowledge needs to be collected using a decentralized approach so that spatial trends and variations can be understood and taken into account when policy decisions are being made by a national organization.

WWW-based GIS Application

Components

The 4-H interactive mapping application consists of five basic user interface components (figure 1).

1. The mapping pane, similar to a display in ArcView, contains the map graphics.

2. The table of contents to the left of the mapping pane is also analogous to ArcView. It allows the user to toggle the visibility of the various GIS layers in the mapping pane.

3. The toolbar above the mapping pane contains buttons and tools that provide the interactive functionality of the application. Custom tools that allow the user to add a data point, delete a data point, and query the map in various ways are provided along with standard built-in functions such as pan, zoom in, zoom out, etc.

4. The information frame is to the left of the mapping pane and provides a place to display text and tabular information to the user. Initially it contains instructions and help information. As the user interacts with the application and queries the underlying GIS layers, the results of the queries are displayed here.

5. Pop-up dialogue windows are created by some of the tools to provide data entry forms to accept user input.

figure 1. Initial national-level user view

User Interface

When the user initially starts the application, they see a map of the United States with state boundaries, county boundaries, major roads, and major water bodies displayed. Local 4-H organizations that have been previously entered are displayed as point symbols. The instructions explain to the user how to zoom into their locality to add a data point for their own local 4-H organization. As the user zooms in to an area, the spatial context information presented to them becomes increasingly detailed. First, additional major roads are added to the map (figure 2) then city boundaries become visible (figure 3). The "feature information" button can be used to find counties, cities, and street names to help guide the user as they focus in on their home area. Alternatively, the "find tool" can be used with a place name or street name to zoom in automatically.

figure 2. County-level zoom with more detailed roads

figure 3. City-level zoom with urban boundaries

Distributed Data Entry

Once the user has found their area, they use the "add data point tool" to digitize the location of their organization's headquarters. Once the point has been digitized, a data entry form is launched in a new browser window to collect information from the user about their organization. This information includes basic data such as their team's name, point of contact person's name, phone number, email address, URL, etc. The form also collects responses to the "Community Technology Self-Assessment" which elicits responses about local conditions with respect to internet access desired by the national 4-H organization (figure 4). The data entry form has some default values pre-assigned by the GIS based on the location of the user-digitized point such as the community name, state, ZIP code, and population. These defaults can be changed by the user if necessary but supplying them as defaults helps to insure consistency in the 4-H communities database by removing chances for spelling mistakes, transposed numbers, etc. The user is also prompted to enter a password so that access to update or delete information is restricted to the person who initially entered the data.

'Community Technology Self-Assessment' data entry form
figure 4. "Community Technology Self-Assessment" data entry form tied to a point location on the map.

GIS Capabilities

The application also allows users to browse the GIS layers and query them. The "feature information button" allows the user to click on a point on the map then select a particular layer. The attribute information from that GIS layer for the feature located at the selected point is displayed in the information frame to the right of the mapping pane. In keeping with the design goal of demonstrating WWW-based GIS capabilities in general, the user may select any of the GIS layers and receive extensive data about them. If they choose to query the 4-H Communities layer, they can see the Community Technology Self-Assessment information collected from the person who interactively entered the data point (figure 5). If they choose one of the reference layers they are presented with reference information about the selected feature such as 1990 census information (figure 6).

figure 5. Results of "feature information button" query on one of the 4-H Communities

figure 6. Results of "feature information button" query on a county

There are a number of other specialized query tools included to demonstrate GIS capabilities. There is a "radius query tool" that the user may use to digitize a point location, specify a radius and select a GIS layer of interest. The "radius query tool" constructs a circle from the point and the radius, intersects the circle with the specified GIS layer and returns a list of the features from the layer that fall within the circle or intersect it. There is also a similar "polygon query tool" that allows the user to interactively digitize a polygon of arbitrary shape on the map; this shape is then used to query the selected GIS layer and list the selected features as with the radius query tool. The "find tool" can be used to search the attribute database for one or more GIS layers to match a search string entered by the user; a list of features containing the desired text string is returned and by selecting one, the user can zoom in to the feature on the map.

Other basic GIS tools are included as well. There is a "coordinate tool" that returns the latitude and longitude coordinates of any point on the map selected by the user. The "distance tool" is available to measure linear distances between points on the map. The "area measuring tool" functions like a planimeter allowing the user to interactively trace the boundaries of an arbitrary area on the map to calculate the enclosed area.

At the time of this writing, the application is still being served and can be accessed at www.4-h.missouri.edu.

Design & Implementation

The 4-H interactive mapping application was implemented using Esri's ArcView Internet Map Server (AvIMS) technology. AvIMS is an extension to ArcView 3.x that uses client-server technology to allow the user's web browser (client side) to transmit requests to an ArcView project running on the server. The ArcView project responds to these requests, performs GIS functions and returns graphic images and html content to the user's web browser. HTML, JAVA, and JavaScript can be used on the client side to customize the web application, control the look and feel of the user interface, and receive user input while Avenue programming is used on the server side to perform the corresponding GIS and database operations and to serve the data to the client (figure 7).

figure 7. Client-server architecture

Future Directions

From a technical standpoint AvIMS has become obsolete and has been succeeded by Esri's ArcIMS product. CARES is in the process of migrating its WWW-based GIS applications to ArcIMS and will be replicating customized features like those described in this paper using the new technology. Interestingly, in our experience many of the customized tools that we have developed remain easier to implement in AvIMS using JAVA 1.02 and Avenue than in ArcIMS. The CARES site can be visited at www.cares.missouri.edu.

This 4-H Interactive Mapping Application was instrumental in demonstrating the possibility of developing a national scale WWW-based GIS for collecting locally-based knowledge through a distributed data entry mechanism. This work served as a catalyst for the development of the Rural Policy Research Institute (RUPRI) Community Informatics Resource Center at the University of Missouri - Columbia. This site can be accessed at www.rupri.org/circ.

References

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H. Archer, and P. Croswell, Public Access to Geographic Information systems: An Emerging Legal Issue, Photogrammetric Engineering and Remote Sensing, 55, No.11, (1989).

S. Langaas, Commercial, off-the-shelf solutions for GIS WWW interfacing, http://www.grida.no/prog/norbal/docs/giswww/giswww.htm (1996).

Z. Peng, 1997. An Assessment of the Development of Internet-GIS, http://gis.Esri.com/library/userconf/proc97/proc97/to550/pap526/p526.htm (1997).

Z. Peng, and D. Nebert, An Internet-Based GIS Data Access System, Journal of the Urban and Regional Information Systems Association, 9, No.1, (1997).

B. Plewe, GIS-Online: Information Retrieval, Mapping, and the Internet, OnWord Press, Santa Fe, NM, (1997).

Author Information

Jim Meyer, GIS Specialist, Center for Agricultural, Resource and Environmental Systems (CARES), University of Missouri - Columbia, MeyerJA@missouri.edu

Chris Fulcher, Ph.D., Co-Director, Center for Agricultural, Resource and Environmental Systems (CARES), and Director, Rural Policy Research Institute (RUPRI) Community Informatics Resource Center, University of Missouri - Columbia, FulcherC@missouri.edu