Automatic Creation and Maintenance of an Organizational Spatial Metadata and Document Digital Library

Charles Kacmar(1), Dean Jue(2), David Stage(3), Christie Koontz(2) 

           (1) Department   of   Computer   Science,   
       (2)Florida  Resources  and Environmental Analysis Center
                    Florida State University

      (3)Growth Management Data Network Coordinating Council
                        State of Florida

                       Authors Addresses:
1203 Love, Tallahassee, FL, 32306-4019, 904.644.9661,
2130 Herb Morgan, Tallahassee, FL, 32306-4015, 904.644.3410, {djue,ckoontz}
3725 S. Calhoun, 112 Bloxham Bldg., Tallahassee,  FL  32399-0950,


This paper reports on the deployment of a digital library to support the Florida Growth Management Data Network Coordinating Council. The system provides locator and access services to spatial metadata (data about data), data sets, and related documents by navigating a spatially-organized directed graph. The work is directed toward state governmental agencies where fully distributed metadata collection and access services within a network environment are necessary. The library is based on a spatial access metaphor, metadata is partitioned and organized into information zones. Information zones provide for dynamic and structured partitioning of metadata and documents within a graph-based network of collection and distribution centers. The information zone concept draws from organizational methods used in traditional libraries.

KEYWORDS: Spatial, geographic, GIS, metadata


Network and computing technologies have become sufficiently advanced to support the design and deployment of large digital document libraries [9, 21]. Although most digital library efforts have or are focused on supporting end-users - such as providing network access to documents, images, video, and audio - we believe that digital library systems can play an even greater role by improving business operations through organizational information management and communications.

Support for business operations and management structures prompted the application of digital library technology to meet the needs of the Florida Growth Management Data Network Coordinating Council (GMDNCC). The Council is a consortium of the eleven major agencies in the state of Florida. It is an organization that is based on a well-defined management structure and relies heavily on interorganizational cooperation and information sharing to support state operations. The digital library system supporting this governmental body is a network- based system that attempts to:

To meet these objectives, the system must facilitate all aspects of the governmental business processes, from the collection of governmental documents and metadata to end-user access from Internet machines located in rural public libraries. The framework for supporting these activities is a spatial-based metadata and document collection process organized into information centers. In this context, the term spatial applies to both human and geographic elements.

Human spatial information management concerns the human's ability to organize and access information by "placing" information in a logical space [13, 23]. Geographic spatial information management concerns organizing and accessing information by geographic characteristics, such as world quadrangle, latitude, longitude, or jurisdictional boundary. The need to support both aspects of spatiality requires that the system support collection, access, and retrieval using geographic elements, and that the system support textual and graphical views over the metadata for people in individual agencies and for the overall organization.

The remaining sections of this paper discuss the implementation of a network-based digital library system that supports the Florida Growth Management Data Network Coordinating Council. The motivation for this approach, elaborated in Section 2, concerns the focus on spatial data and a spatial access paradigm, discussed in Section 3. Section 4 discusses the mechanisms for collecting data and documents and facilities to manage the document collection. Section 5 discusses the operation and access facilities to these documents. Section 6 reports on the current status of the research, discusses future directions and differences between this approach and others. Section 7 provides a summary.


Most existing networked document facilities for governmental information depend on text to classify and support access [10]. HTML [5], WAIS [14], and Gopher [2] are the preferred methods of access. Even though some systems provide graphical elements (e.g., icons, images, maps) in their displays, these elements are generally used as "window dressing" to the primary method of access - text. Experience has indicated that researchers and users of [geo]spatial data require a different access paradigm [15], that is, text-based systems do not provide an access paradigm that matches the cognitive models employed by spatial data users [10].

Another issue concerns the manner by which existing libraries and document repositories are maintained. Existing systems usually organize documents by convenience of the facility serving the information and not necessarily along content or conceptual means. Spatial data users require the creation and coordination of geographic maps with metadata and documents. To do this using the system structures, protocols, and network access methods listed above requires a level of human and computing resources that most governmental agencies cannot afford. Resources, in the form of labor and technical expertise, are needed to create and maintain access structures and manage document repositories. Maintaining access structures in any form - menus, hypermedia links, or queries - can be difficult and incur significant expense.

To address these problems, we extend the operational framework (i.e., buildings, floors, shelving, cataloging systems) of today's public libraries to create a model for organizing and partitioning electronic library collections on a global scale. We define and adopt the concept of information zone to support the management and facility structures within governmental bodies. This conceptual framework divides the digital library into geospatial-information zones, where each zone contains a collection of documents that are related. Access and organizational structures to zones are supported by software and provide for two types of partitioning - (1) mutually exclusive zones, where each zone contains a distinct set of documents, and (2) overlapping zones, where the same document may appear several times to provide for multiple paths of access. To the end-user, this partitioning is completely transparent - users are generally unaware and do not care where the information is stored. From a management perspective, this framework allows state information managers to parallel the real management structures within the government. For example, the system can support a traditional vertical organization within a specific agency, as well as support interrelationships among data, a necessary and important element of the eleven member agencies of the GMDNCC.


Geographic spatial data has traditionally been available to researchers and other users as paper maps [12]. The U.S. Geological Survey's (USGS) quadrangle maps covering the entire nation at a 1:24,000 scale are one example. In the past decade however, paper-based spatial data has gradually been replaced with electronic systems and data sets. The digital medium allows for the representation of not only the individual map features, but also the collection of attributes associated with each feature. These features, realized as attribute/value pairs, are generally stored in relational files and associated at time of access to form the graphical map display.

Spatial data content and management is driven by three primary elements: attributes, time, and user tasks. Attributes define the contents and characteristics of spatial data as well as some of the limits of how the data can be used. For example, dimensional attributes can provide the height of a forest canopy, area of a city, width of a road, or coordinate reference (e.g., latitude and longitude). Some attributes supply value while others, such as a coordinate reference, serve to define the positional location of a graphical feature relative to other features. This relationship provides for the dynamic composition and analysis of spatial data from multiple sources with similar degrees of accuracy. For example, a digital soils map of a county could be superimposed on a digital hydrography map of a much larger region if both data files were gathered at similar levels of accuracy and their coordinate reference points indicated an overlap in the maps' area of coverage. The new map composition could then be used to analyze, for instance, soil types relative to the proximity of major rivers.

Temporal elements determine the scope of use for spatial data and provide a chronology for recording variations over time. These elements allow a researcher to use temporal data as a basis for analyzing variations. For example, a meteorologist may package a collection of map displays into an animation to better understand the path of a hurricane.

Spatial data are produced in two primary formats, raster and vector [3]. Raster is a grid-type format most often used to interpret color and gray-scale photographs of remotely-sensed scenes (e.g. satellite imagery). The imagery is stored as dots or pixels, each associated with a different shade, density, or other attribute value. Examples of data sets collected and stored in raster format include those collected by NASA's earth- observing systems (EOS), the National Oceanic and Atmospheric Administration's Advanced Very High Global Resolution Radiometer (AVHRR) instrument data, and the Landsat multispectral data from Earth Observation Satellite Company (EOSAT).

The vector format represents spatial data by points, lines, or polygons. Small objects (e.g., water hydrant locations) are represented by points while linear features such as roads, rivers, and contour lines are defined by lines with x and y coordinate end points. Polygons, which are composed of individual lines, are used to represent areas (e.g., countries, voting districts). The Census Bureau's TIGER Line files, containing most street segments in the U.S., are an example of spatial data in vector format.

Digital spatial data sets are viewed using geographic information systems (GIS). The GIS can combine, overlay, add, subtract, multiply, and divide spatial features and their attributes. This allows researchers to see patterns in spatial data as well as make dynamic interpretations of those data. Complex questions from the researcher can be presented to the GIS.

Accessing spatial data spatially

Digital spatial documents consist of data with tens or hundreds of feature variables stored as attribute/value pairs. Meaningful access to spatial data may require using a single attribute as an access or search point. For example, a demographer may need to determine if the transportation layer of the USGS Digital Line Graph (DLG) file for a county contains 4-lane bridges or railroad crossings, or a microclimatologist may need to determine if there are ponds of a certain kind in the area of interest. These variables and values are usually recorded as attributes in the document but currently are only accessible if a full GIS environment is used to open the actual spatial document itself. The necessity of GIS environments to open and read spatial documents makes direct investigation of the document without first knowing its limitations as presented in the metadata often futile. In essence, traditional abstracting and indexing is not sufficient for these methods of access. Access paradigms must be augmented by availability of metadata and be supported by a data dictionary/codebook.

Traditional boolean word operations are not optimal for determining whether a spatial document is relevant to a particular task. Providing a list of geographic named features at all levels of resolution included in a particular spatial document is a major problem because of the disagreement over names, the constant changing of names (e.g., Leningrad back to St. Petersberg), and the multiplicity of names for the same place. Work has begun in developing extensions to WAIS to support boolean searches for spatial data [20] but the best approach for integrating spatial searching/querying with existing access tools is still unclear at this time. Research is also ongoing regarding the use of object-oriented structures for storage and retrieval of spatial digital data [7].

Spatial data files are complex objects and it is often difficult to construct locator and description records for them because of the issues mentioned above as well as the ease with which spatial data may be misused. For example, users often will zoom-in beyond the resolution of the spatial document. The display will show no objects at a location in that document, when in reality, objects are present if another more detailed view of the document had been used (the raw data was collected at a level of resolution different than what is currently displayed).

Thus, current methods of supporting access to spatial documents, using locator records and text-based organization and searching, are simply not adequate for spatial data [10]. Problems concerning data type and number of access points, and the need for spatial operators to provide effective retrieval, make spatial digital information somewhat distinct from other forms of digital data. As a result, the optimal access paradigm for spatial data is spatial access -navigation through a geographic space [1]. To support this, geographic spaces must manifest as digital maps, populated with selectable features that support navigation. More importantly, spatial digital libraries must provide for the collection, organization, and access of spatial data through spatially-oriented tools.


The focus of this paper is a digital library system that is a collection of software components that are designed to support all aspects of [geo]spatial metadata and document collection and management for the eleven member agencies in Florida's GMDNCC. The specific focus on spatial metadata and documents is due in part to increases in the production of digital spatial data sets, and a needs analysis that reports that eighty to ninety percent of certain governmental data has some aspect of spatiality [12].

The system supports the management structure of the GMDNCC by allowing information managers in an agency to define metadata and documents produced by the agency. Access structures unique to that agency are supported automatically. Moreover, access paths to metadata and documents without regard for agency are also provided automatically. This enables the user to "cut across" the vertical structure of government to find, view, and retrieve information produced by various agencies.

The process of contributing information to the library begins when an agency information manager creates a metadata (catalog) record and identifies the publically available documents associated with the metadata. Metadata includes attribute/value pairs that provide for the capture and analysis of spatial objects and features. Metadata does not provide a sufficient level of abstraction for human access. For this reason, a higher level of representation is needed -a representation that allows users to document and express conceptual properties of data. This requires that the metadata contain high-level conceptual representations such as descriptions and abstracts. This information is captured using the metadata collection facility and used by librarians-to facilitate the construction of access structures that are more appropriate to the task-based needs of information managers and end-users.

The design of the metadata collection facility was guided by several important factors. First, different spatial data sets need different metadata representations and for this reason, the tools needed to present and collect metadata in different formats. Second, metadata needs to be checked to insure accuracy. This is an extremely difficult task, especially since much of the metadata information is conceptual in nature or "codified." In some cases, spatial metadata cannot be validated automatically (e.g., the world quadrangle from which an environmental sample was collected). Third, metadata may need to be stored in a geographically distant location. In essence, the metadata collection facility must serve as a "front-end" to post- processing or distribution of the metadata record.

Figure 1: Metadata collection tool.

Referring to Figure 1, the metadata collection tool divides the screen into three regions. Menu/action buttons appear along the lower portion of the window, field names appear along the left side, and field data appears and is entered in the main portion of the window. The design of the screen is form fill-in [22], but also support radio menus and selection lists. Clicking on a field name provides the user access to the codebook for the field. Thus, the order and content of fields and the immediate availability of the codebook enhance the metadata collection and maintenance processes.


Various modes of operation are supported by the metadata collector. As shown in Figure 2, the metadata collector can (1) collect and invoke processes to immediately and automatically catalog the information; (2) send the metadata information to a cataloging center where it is processed automatically; or (3) send/store the metadata to a location where a human cataloger or librarian reviews and catalogs the information. In the latter case, this allows for the collection of metadata at a user's location followed by transmission to a remote location where a human librarian evaluates the metadata for accuracy. The librarian correct any defects, possibly calling and discussing the contents of the metadata with the submitting user, and then accepts the metadata into the digital library where it is cataloged.

Figure 2: Modes of operation.

The metadata collection tool provides three important characteristics. First, it supports on-line access to the codebook. Second, the "menu/action buttons" that appear in the lower area of the screen are configurable and each is associated with specific processing facilities. This allows someone to decide what actions are available to users for each type of metadata record. Third, the fields that comprise the metadata records are based on a semi-structured format [17] and are modelled after the Internet Engineering Task Force (IETF) specification [6]. The metadata collector and metadata format provide for complete definition of metadata records. This allows the metadata content and format to be tailored specifically to the type of data and documents to be stored in the library. Figure 3 illustrates how this is accomplished.

Referring to Figure 3, the metadata template serves as a "blueprint" for describing the elements of spatial documents the user wants to register with the library. The first 4 lines define the "action buttons". Each button is associated with a shell script or program that is executed when that button is pressed. The remaining entries in the template define the fields that will comprise a metadata record of this type. Three types of fields exist in the template shown in the figure - radio button (R), numeric (N) and character (C). The numbers following the field type indicate, respectively, number of entries in a menu or number of lines of data in the field, and for data entry fields, width of each line, and number of instances of this field in the record (repeating field).


  Agency               R  3
  Contact_Name         C  1  50 1
  Contact_Phone        C  1  15 1
  ShortDescription     C  1  80 1
  LongDescription      C  5  80 1
  Intended_Scale       C  1  10 1
  Percent_Complete     C  1  5  1
  Update_Schedule      C  5  80 1
  Update_Cost          N  1  5  1
  Source               C  3  80 3
  Contact_Name         C  1  50 1
  Keywords             C  8  25 1

              Figure 3:  Metadata record template.


Metadata, documents, and data sets comprise the contents of the digital library. Documents may reside anywhere on the Internet with access to them provided through URL's entered within fields. All access is supported by Mosaic [19, 25] or through FreeNets. (see footnote) [16]

The entry screen into the library is shown in Figure 4. Five access paths are provided (1) field-name index, (2) inverted index, (3) agency-specific view, (4) spatial/map, and (5) term query.

Figure 4: Entry screen.

Navigating into the field-name and inverted index paths presents the user with screens as shown below, respectively. The user traverses the graph structure by navigating the desired item.

Figure 5: Screen shots of the field-name (top) and inverted index (bottom) paths.

Navigating into the spatial/map access path allows the user to locate and access metadata records and documents by clicking on a geographic area (grid).

Figure 6: Spatial/map access path.

Figure 7: Thematic view.

Figure 8: Aerial photography view.

The agency view access path supports access through a hierarchically structured directed graph. Shown in Figure 7 is the highest level access document into the thematic records and documents. Figure 8 shows the highest level document into the aerial photography records and documents.


The digital library system described in this paper provides metadata and document collection, automated creation and management of a networked digital library containing these data, and geographic (graphical map) access to the information for the state of Florida's Growth Management Data Network Coordinating Council (GMDNCC). During the past year, we have demonstrated the ability to support end-user needs through automated cataloging facilities that enhance locating, accessing, and retrieving information. The framework for this approach is a set of collection, distribution, and access centers within designated information zones. These centers can be housed in government agencies, private businesses, or more importantly, state, county, and local libraries. The physical structure that supports the library system is of no concern, instead, the goal is to provide an integrated set of information centers that support and reflect the State's governmental management structure and information access needs.

Previous approaches (see Frank [10] for a metaanalysis) have resolved some of these problems through the creation of support tools that supplement geographic information systems, and in some cases, interpret and display data in spatial data sets. For example, the Louisiana Coastal Geographic System Network (LCGISN) [18, 11] and Northwest Land Information System Network (NWLISN) use text-based high-level menus to provide the user with advanced cataloging, search, and access services over a large centralized database of spatial metadata. When the user finds a relevant data set, it is viewed by launching the GIS from the access facility. MITMapper [8] provides users with both text and graphical access facilities to a centralized database of metadata. Metadata is partitioned into classes and is browsed through a series of text menus or by clicking on a map graphic. Once the user locates the spatial data set of interest, the GIS system is launched from the metadata browser. The importance of these efforts concerns the variety of access paths provided to users to locate relevant data.

In an effort to encourage and coordinate spatial data efforts throughout the U.S., the USGS began sponsoring additional research efforts that may lead to a national spatial data locator and access service [24]. Users will locate spatial data sets using metadata access facilities. This approach will provide both text (via WAIS [14] ) and graphical-based (via Mosaic [19, 4, 25] ) network access to spatial information.

The approach presented in this paper is consistent with the USGS effort and provides for an integration of components involving metadata collection, distribution, and network access within a spatially-oriented, navigational-based, graphical, locator and access library system. This approach provides for agency specific access paths to metadata and documents, while at the same time, enforcing state-wide standards to increase the consistency and integrity of metadata.

Over the past year, the digital library system described in this paper has supported a collection of the major spatial metadata records for the state of Florida. This collection, called the Florida Data Directory, is a collection of metainformation that is partitioned into three major data types: survey/thematic, aerial photography, and satellite imagery. To further demonstrate the ability of the system to support document and data set collection and access, the Florida Game and Fresh Water Fish commission supplied an environmental habitat report and spatial data sets for all sixty-seven Florida counties. The data sets are linked to the environmental report providing end-users access to all elements used in the production of the report.

Current work is focused on enhancing the library system in several ways. First, information managers require tools to catalog and distribute documents. These tools must capture all of the attributes associated with a documents while at the same time enforcing metadata standards. Work on developing an enhanced metadata collector is in progress.

Second, the system is attempting to reduce the costs of government, eliminating redundancy and reducing the time required for information managers and other state employees to locate and retrieve information produced by other agencies. Data is an expensive resource that should be shared among all agencies. Locator and notification services are two mechanisms being used to enhance awareness of relevant data for state employees. Work is continuing to enhance automated awareness components.

Third, the system should operate within the state's infrastructure. Since most state agencies do not have the resources (human or hardware) to do their own document production and storage, the state library system, especially librarians, should play a critical role in every aspect of information management - cataloging, collection, distribution, reference, and access. Ideally, librarians will work with agencies to identify documents for cataloging and placement into repositories, verify and validate metainformation, work with organizations to establish relevant access paths into the data, and assist end-users in accessing information using terminals in public libraries.

Fourth, the system should provide better support for both the vertical and horizontal management structures that exist within state government. In the existing system; metadata and its associated geographic elements are defined using text; a single library structure is supported; agency-specific views over metadata are provided but they require some manual intervention. The new version, expected in early Summer 1995, will broaden the focus of automation to support (1) metadata creation using graphical geographic elements; (2) support multiple digital libraries within a logical management structure; and (3) automatically create and manage the entire repository, which includes the depositing of metadata, documents, and the data.


Spatial data is complex data composed of hundreds of attribute/value pairs that define geographic and abstract features. Spatial data has been available to researchers and other users as paper maps, but increasingly, spatial data is collected and maintained in digital data sets. These data sets generally exist as separate entities from their metadata, in many cases hindering the ability to locate and access spatial data sets from network locations. Moreover, this situation has been a continuing problem for the field, primarily because network- oriented systems do not provide sufficient spatial paradigms to access spatial data sets.

A spatial digital library offers a solution to these problems by providing the information manager with tools that support cataloging, locator, and access tasks. This paper reports on the development and deployment of a digital library system that automates the creation and management of a geospatial digital library, improving end user access to information through geographically-based (spatial) textual and graphical directed graphs. This approach is based on a spatial access metaphor that organizes digital libraries into information zones. The tools supporting this library provide for dynamic and structured partitioning of metadata and documents within a graph-based network of collection and distribution centers. The result is a digital library system that can model the management structure of an organization, but also allows users to cross organizational boundaries during information creation, navigation, search, and retrieval. Ideally, librarians with their cataloging expertise and infrastructure, will facilitate all aspects of digital library operations, from identifying relevant documents to include in the collection, to assisting agencies in creating custom access paths for public users. Current work is focused on enhancing the existing prototype, with significant effort devoted to complete automation of the repository.


The authors would like to especially thank the following individuals and agencies who provided input or participated in this project: U.S. Geological Survey for sponsoring some of the metadata analysis, Dr. Myke Gluck of the School of Library and Information Studies at Florida State University for his assistance in user interface and library issues, and Dion Goh, Burak Imir, Lo Ko, Vivian Lee, Xiaozhong Liao, Wan-Hua Lin, Jason Orendorf, Ken Sheffield, Fang Zhao, in the Department of Computer Science at Florida State University for their contributions in the development of the systems supporting this research, and the Tallahassee FreeNet for providing access to the library.

This work is supported in part by the Federal Geographic Data Committee of the U.S. Geological Survey under Cooperative Agreement No. 1434-94-A-1288.


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