Geospatial Web services and geoarchiving: new opportunities and challenges in geographic information services.ABSTRACT
Over the course of the past fifteen years the role of Geographic Information Systems geographic information system (GIS)
Computerized system that relates and displays data collected from a geographic entity in the form of a map. The ability of GIS to overlay existing data with new information and display it in colour on a computer screen is used primarily to (GIS) has changed significantly. Initially the role of the map library was confined con·fine
v. con·fined, con·fin·ing, con·fines
1. To keep within bounds; restrict: Please confine your remarks to the issues at hand. See Synonyms at limit. to that of building and providing access to collections of hard copy maps and imagery. Later, digital data, whether on CD-ROMs or network based, was added as a new type of resource within that collection and service model. By the late 1990s some academic libraries began to take on a Web map server Noun 1. Web Map Server - a computer program that produces maps of spatially referenced data dynamically from geographic information
Web Map Service role, providing interactive Web mapping access to collections of digital geospatial data. In the new era of distributed, interoperable map services, libraries will have an opportunity to explore new roles as portals to streaming content available in the form of geospatial Web services (1) Loosely, any online service delivered over the Web. Such usage appears in articles from non-technical sources, but not in IT-oriented publications, because definition #2 below describes the correct use of the term. . At the same time, the increasingly ephemeral Temporary. Fleeting. Transitory. nature of digital geospatial content will make even more critical the need to address the long-term digital preservation challenges that are facing geospatial content.
This article focuses on two major geographic information issues facing academic libraries as well as libraries in general. First, what role should libraries play in the development and utilization of emerging geospatial Web services? Second, how should libraries address the challenge of long-term preservation of digital geospatial data in light of a shift to distribution methods that make the content ever more ephemeral?
Over the course of the past fifteen years the role of Geographic Information Systems (GIS) has changed significantly. Initially the role of the map library was confined to that of building and providing access to collections of hard copy maps and imagery. Later, digital data, whether on CD-ROMs or network based, was added as a new type of resource within that collection and service model (Journal of Academic Librarianship, 1995, 1997). By the late 1990s some academic libraries began to take on a Web map server role, providing interactive Web mapping access to collections of digital geospatial data. In the new era of distributed, interoperable map services, libraries will have an opportunity to explore new roles as portals to streaming content available in the form of geospatial Web services. At the same time, the increasingly ephemeral nature of digital geospatial content will make even more critical the need to address the long-term digital preservation challenges that are facing geospatial content.
This article will focus on two major geographic information issues facing academic libraries as well as libraries in general. First, what role should libraries play in the development and utilization of emerging geospatial Web services? Second, how should libraries address the challenge of long-term preservation of digital geospatial data in light of a shift to distribution methods that make the content ever more ephemeral? Specific experiences with engaging geospatial Web services and with instituting preservation-focused action responses will be drawn from the North Carolina State University History
Area, 52,586 sq mi (136,198 sq km). Pop. Geospatial Data Archiving Project, a cooperative effort with the Library of Congress and the NC OneMap Initiative.
BRIEF OVERVIEW OF DIGITAL GEOSPATIAL DATA SERVICES IN ACADEMIC LIBRARIES
There are many components of academic library GIS services. At the core is the data collection, but accompanying the data is a mix of services that vary from campus to campus. A brief summary of typical service components follows.
Libraries acquire, license, catalog, make discoverable, archive, and carry out value-added processing on digital geospatial data. While, in the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. at least, much data is available in the public domain, the data is not always organized or readily accessible in such a way as to allow the user to easily sort through the wide range of data options available, and effort is required to make such freely available data discoverable. Furthermore, in order to improve data availability Refers to the degree to which data can be instantly accessed. The term is mostly associated with service levels that are set up either by the internal IT organization or that may be guaranteed by a third party datacenter or storage provider. it is sometimes necessary to acquire and license additional commercial or fee-based government data for use. In some cases libraries also engage in large-scale value-added work--retiling, projecting, or otherwise converting and reorganizing data resources into a more convenient form for the libraries' target audience.
Data Discovery Tools and Support
Libraries support the discovery, selection, and use of geospatial data. While the most common form of promoting access to data collections has been the development of Web documentation for data collections, in some cases searchable databases Refers to databases on the Web that are searchable by typing in a query. The term is quite redundant because all databases are searchable. In fact, that is one of their major features. of geospatial metadata Geospatial metadata (also geographic metadata, or simply metadata when used in a geographic context) is a type of metadata that is applicable to objects that have an explicit or implicit geographic extent, in other words, are associated with some position on the are also made available. Data resources may also be included in the library's catalog, but the catalog is not usually the most effective vehicle for exposing or searching for digital geospatial data.
The line between providing reference support for finding and selecting data and providing actual technical support for using the data is a blurry one, and it has become more common for academic libraries to play a prominent role in providing technical support to GIS users. At NCSU, for example, the library holds one of four "right to call" spots for the campus Environmental Systems Research Institute (ESRI (Environmental Systems Research Institute, Inc., Redlands, CA, www.esri.com) The world's leading developer of geographic information systems (GIS) software, including programs that plot ZIP codes and addresses, demographic information and detailed, color-coded data. ) site license and provides technical support as needed as needed prn. See prn order. to campus users. Libraries also play varying roles in supporting campus software licenses In computing, software that is copyrighted and licensed under a software license is done under a variety of licensing schemes. For end-users there are proprietary licenses and there are free software licenses, and there are proprietary Within these schemes are further classifications. , facilitating distribution of software, and troubleshooting installations.
Workshops and Training
As an extension of reference and technical support many libraries offer workshops on a variety of topics such as introductory GIS, data discovery, or use of specific software tools. The mix of workshops offered often reflects the sort of reference and technical support demands placed on the library. Increasingly, in-library workshops have now been complemented by and even supplanted by online training resources. At NCSU, for example, the library supports over 600 registrations per year for the ESRI Virtual Campus online courses.
Marketing and Outreach
Another academic library function, which goes hand-in-hand with workshops, is marketing and outreach--promoting geospatial resources and services to the campus community. GIS activity typically initially takes root in one or just a few core departments where there is a high level of activity and support. Meanwhile, latent demand exists in a broad range of academic disciplines where awareness of geospatial tools and resources is lacking, or where there is a perceived barrier to entry in terms of lack of access to tools, data, training, and support. Libraries, as a neutral space focused on customer service, are well positioned to cultivate new GIS users by promoting the use of geospatial tools and content and by providing ready access to software, data, training, and support. At NCSU the number of academic departments engaged in GIS grew from fewer than ten to thirty-five within just a few years as a result of combined campus and library efforts to develop a campus GIS infrastructure.
Evolution of Technical Approaches to Delivering Geospatial Data
The manner in which libraries have provided access to geospatial information has changed significantly in recent years, with analog map and image offerings increasingly being supplemented by or replaced by digital resources. At NCSU campus-wide networked access to data was initiated in 1993, with data made available both for download and for use online from GIS workstations in a networked environment. By 2000 one began to see more libraries offering Web mapping services, making the GIS content available to a much broader audience, including those who otherwise lacked the skills, software, and data access ordinarily needed to utilize GIS content.
The Early Library Experience with Web Mapping
While the Web mapping approach was initially fruitful--and still is in some contexts--these library-based map servers have increasingly risked becoming liabilities to the extent that volatile state and local content is included. State and local agency data producers are typically better positioned to manage data updates, and the number of available state and local map servers has risen steadily since 2000. In North Carolina, for example, the number of county map servers increased from 15 in 2000 to 77 out of 100 counties in 2005 (NCSU Libraries, 2006a). User demand for county and city data is high because it is larger scale, more detailed, more current, and more accurate than state and federal alternatives. Furthermore, many resources, such as cadastral ca·das·tre also ca·das·ter
A public record, survey, or map of the value, extent, and ownership of land as a basis of taxation.
[French, from Provençal cadastro, from Italian data, zoning, and building footprints, tend to be available only at the local level. Meeting real user demand for data has increasingly required that local content be made available, yet the rate of update of that data has made it increasingly unfeasible to integrate and successfully update such content within library-based Web mapping services. The existence of stale data hosted on library servers, coupled with concern some data producers have about liability issues, have made the library Web map servers an increasingly untenable option. At NCSU Web map services, which began in 1997, were ceased in 2001 in deference to emerging state and local map services.
DATA INTEROPERABILITY AND EMERGING GEOSPATIAL WEB SERVICES
By the year 2000 producer-operated map servers were proliferating Proliferating is the multiplication of a certain thing. Often it is used as a biological term to describe the increase of cells due to cell division.
Look under proliferate or proliferation for more details. , but these emerging federal, state, and local map servers remained data islands that could be viewed only in isolation from one another. There was no way to zoom in and see federal, state, and local content together for a particular location. There was also no easy way to view adjacent county or municipal services This article or section deals primarily with the United Kingdom and does not represent a worldwide view of the subject.
Please [ improve this article] or discuss the issue on the talk page. in a side-by-side manner. Social, environmental, and economic processes did not stop at county borders, but local map services did.
Around the same time, however, the various initiatives of the Open Geospatial Consortium The Open Geospatial Consortium (OGC) is an international voluntary consensus standards organization. In the OGC, more than 330 commercial, governmental, nonprofit and research organizations worldwide collaborate in an open consensus process encouraging development and (OGC OGC Office of Government Commerce (UK government)
OGC Open Geospatial Consortium, Inc.
OGC Office of the General Counsel
OGC Open GIS Consortium, Inc. ) began to bear fruit and some key initial steps toward data interoperability were made. Data interoperability is necessary to integrate disparate data resources; allow sharing of content; allow interoperability between resources in different formats, commercial software environments, and coordinate systems coordinate system
Arrangement of reference lines or curves used to identify the location of points in space. In two dimensions, the most common system is the Cartesian (after René Descartes) system. ; and facilitate service chaining (Reichardt, 2005). A key initial OGC specification, the Web Map Server (WMS WMS Warehouse Management System
WMS Web Map Service (open geospatial consortium specification)
WMS West Middle School (Rochester Hills, MI)
WMS Workforce Management Software
WMS Wechsler Memory Scale ) 1.0 specification, was adopted in 2000 (OGC, 2004), and activities related to the Web Mapping Testbed led to a subsequent explosion in the development of WMS services (Doyle, 2000). Initiatives such as the National Map, at the national level, and NC OneMap, at the state level, helped to further the integration of federal, state, and--increasingly--local map services in a flexible interoperable environment. In North Carolina, for example, by virtue of extensive outreach carried out by the NC Center for Geographic Information and Analysis and the U.S. Geological Survey The term geological survey can be used to describe both the conduct of a survey for geological purposes and an institution holding geological information.
A geological survey with their partners, the number of state and local WMS services in the state grew from two in 2002 to seventy-four in February 2006 (NCSU Libraries, 2006a; NCGICC, 2006a). As a standalone stand·a·lone
Self-contained and usually independently operating: a standalone computer terminal. system as well as a component of the National Map, NC OneMap provides services in the context of statewide needs while also feeding content directly into the National Map system (NCGICC, 2003).
The rapid growth in availability of geospatial Web services has been followed by the development of new services focused on geospatial Web service discovery and integration. Initial work in ESRI's Geography Network, available from 2000, was followed by development of the National Map Catalog and later Geospatial One-Stop The Geospatial One-Stop (GOS) is a geoportal that provides public access to geospatial information as part of a United States e-government initiative (see OMB Circular A-15). . At the same time, commercial geospatial Web services also began to proliferate pro·lif·er·ate
To grow or multiply by rapidly producing new tissue, parts, cells, or offspring. , with offerings such as ArcWeb Services ArcWeb Services is a GIS product offered by ESRI to provide Web-oriented spatial data services. ArcWeb Services is a Hosted GIS that provides geographic web services (W3C/SOAP and others) to web browsers and other Internet-enabled technology. from ESRI and other commercial services from firms such as TopoZone. While such commercial mapping services initially took the form of noninteroperable Web mapping services, it has increasingly been the case that these offerings are interoperable services based on OGC interoperability specifications, Simple Object Access Protocol (protocol) Simple Object Access Protocol - (SOAP) A minimal set of conventions for invoking code using XML over HTTP.
DevelopMentor, Microsoft Corporation, and UserLand Software submitted SOAP to the IETF as an internal draft in December 1999.
Latest version: SOAP 1. (SOAP), or Application Programming Interfaces (API (Application Programming Interface) A language and message format used by an application program to communicate with the operating system or some other control program such as a database management system (DBMS) or communications protocol. ) that support application integration.
The Attraction of Geospatial Web Services
Geospatial Web services are potentially attractive to libraries and their users for a number of reasons:
* The services are available in a time and location independent manner.
* Access to extremely large datasets is possible even over low bandwidths.
* The most current data is readily available and data update does not require local maintenance action by libraries or other intermediate information providers.
* Differences in native formats and coordinate systems can become less of a barrier to use.
* Access to data can be more efficiently offered for regions where demand does not merit static data purchase.
Map services can be used in a broad range of situations, from complex projects involving application fusion to rather basic one-off uses. For example, one of the common uses of paper maps seen in the map library is that of tracking down the locations and coordinates of specific places on USGS USGS United States Geological Survey (US Department of the Interior) topographic quad sheets. Since the late 1990s there have been a variety of commercial and public domain servers that allow users to examine topographic maps (Data West Research Agency definition: see GIS glossary.) A map depicting terrain relief showing ground elevation, usually through either contour lines or spot elevations. The map represents the horizontal and vertical positions of the features represented. online, identify coordinates, and make annotations. There is no question that examining a topographic map by holding the large-format analog copy is preferable, from an ergonomic ergonomic - Concerning ergonomics or exhibitting good ergonimics. or aesthetic perspective, to looking at a smaller map area on the computer screen, or that many map analysis tasks can be more effectively carried out using large-format analog maps and images. Yet when one factors in issues such as convenience of access, travel time to the library, expanded resource availability, and other factors, the Web-based option becomes an attractive alternative for many map uses.
Drawbacks of Geospatial Web Services
There are of course many drawbacks to utilizing geospatial Web services or relying on them as a core information resource within geographic information services See Information Systems. , including the following:
* Application performance when using Web services will frequently not match that which can be achieved using locally loaded data.
* Uptime reliability can be a problem, lead to service chain failures, and threaten project work.
* Some services are of a demonstration nature and can disappear without notice.
* While the content underlying Web services might be updated with some frequency, some applications may have a need to rely upon static, snapshot content for consistency in results and analysis.
* Screen-generated maps are aesthetically and ergonomically no match for large-format analog maps and images.
Geospatial Web services are clearly more useful in some situations than others, depending upon application and user requirements. These services are probably most useful when
* the user needs the most current data;
* the data is subject to frequent change;
* the user needs to make use of extremely large datasets, perhaps over lower bandwidth connections;
* the user wishes to preview the data prior to acquiring it;
* the user just needs the data for background use;
* the data needs to be integrated into remote or portable devices;
* the data is not otherwise available or cannot be efficiently acquired and stored for local use.
Integrating Geospatial Web Services into the Library Environment
Awareness of and promotion of these emerging Web services are still rather low both on the part of end-users and on the part of academic libraries. Integrating and managing access to services presents some problems that are very different from those associated with locally hosted content, including the following:
* Geospatial Web services have been difficult to discover and select from.
* In the case of commercial services, sustainable licensing models that work on a campus scale have yet to be worked out to satisfaction (problems include allowing for the volume of requests related to simple operations such as pan zoom, the ability to restrict access to authorized users authorized user Radiation physics A person who, having satisfied the applicable training and experience requirements, is granted authority to order radioactive material and accepts responsibility for its safe receipt, storage, use, transfer and disposal , and anticipating an unknown volume of requests).
* Linking data resources with services that act upon them has been a sticky issue, with metadata standards and practices not adequately addressing the linkage of data resources with services that act upon them.
* Rights issues and approved use are in many cases ambiguous, with Web services in something of a "Wild West stage" (for example, it is not clear whether it is acceptable to extract data from ArcIMS services through ArcGIS connections; this is technically possible but not typically an intended use of the service).
* Integrating Web services into the physical browsing environment of the map collection in order to stimulate awareness of these new resources is tricky given the transient nature of such services.
With regard to the issue of physical browsing, while libraries have become increasingly if not overwhelmingly digital, the map room still provides a rich and effective browsing environment. While volatile resources such as Web services do not lend themselves easily to hard-coded representation on shelving shelv·ing
1. Shelves considered as a group.
2. Material for shelves.
3. An incline; a slope.
1. material for shelves
2. or in map cases, emerging mobile device technologies might, in time, make it more feasible to integrate discovery and use of these resources within the context of the physical browsing environment.
Possible Library Roles vis-a-vis Geospatial Web Services
So what might academic libraries do to promote and facilitate access to geospatial Web services? Some possible roles might include facilitating discovery of services; producing new map services to fill the gaps in service availability; building new map portal services on top of existing map services; licensing commercial Web services for use; and utilizing Web services consumption data to inform collection development planning.
Facilitating Discovery and Selection Libraries can support user discovery and selection of resources by incorporating such services into catalogs, GIS data collections, and the physical map room browsing environment. Just as libraries provide support in user selection of maps or datasets, support can also be offered in selecting from among competing service options. The notion of the reference interview, as it applies to geospatial data, can be extended to geospatial Web services.
The more traditional geospatial data-focused reference interview will tend to focus on content issues, a subset of which might include the following questions:
* Data extent: Does the data cover the study area as required?
* Thematic content: Does that street dataset have street centerlines or curbs and gutters?
* Attribute availability: Are there street addresses? Are they complete across the entire dataset? Is the format friendly to geocoding processes?
* Currency: How recently was the data produced? What real world time period does it represent? How concurrent is it with other data to be used in the project?
* Format: Is the data in a vector format In CAD and computer graphics, a vector format is used to represent the vector graphics on the screen.
This approach was used earlier in the 1970s when cathode ray tubes would draw line segments representing edges of a BREP. that the project's software can support or at least convert without unacceptable data loss? In the case of imagery, has a level of compression been used that entails unacceptable data loss?
* Openness of licensing: Can the data be copied off of the CD-ROM CD-ROM: see compact disc.
in full compact disc read-only memory
Type of computer storage medium that is read optically (e.g., by a laser). or server? Can maps created from the data be used in publication? Can the data be used in a Web mapping application? Can a value-added derivative of the data be redistributed re·dis·trib·ute
tr.v. re·dis·trib·ut·ed, re·dis·trib·ut·ing, re·dis·trib·utes
To distribute again in a different way; reallocate.
Adj. 1. ?
* Ease of access: Can the data be downloaded right now? In the case of very large datasets, is it possible to connect directly to the resources and use the data across the network? Is it possible to extract data for extremely large areas, or must one make numerous much smaller extractions to assemble data for the study area?
* Coordinate system, datums, etc.: Will it be necessary to re-project the data? Will a datum The singular form of data; for example, one datum. It is rarely used, and data, its plural form, is commonly used for both singular and plural. conversion be necessary? Is this information even recorded in the metadata?
In the Web service context, some of the content facets, such as format, can become less important, while some additional service or "functional" metadata come into play. These facets might include the following:
* Type of service: Image service, feature service, geocoding service, etc.
* Access protocol: ArcIMS image service, ArcIMS feature service, WMS, WFS WFS Wegfahrsperre (German: drive away blocking system)
WFS Web Feature Service
WFS World Future Society
WFS World Food Summit
WFS Wave Front Sensor
WFS Wolfram Syndrome
WFS Wire Feed Speed (welding) (Web Feature Service), SOAP, and other methods such as the Google Maps Google Maps (for a time named Google Local) is a free web mapping service application and technology provided by Google that powers many map-based services including the Google Maps website, Google Ride Finder and embedded maps on third-party websites via the Google Maps API. Is the service exposed through a protocol that is compatible with the user's technical environment?
* Reliability and uptime: Will downtime The time during which a computer is not functioning due to hardware, operating system or application program failure. impact project work or service chaining? Is this a demonstration service that is liable to disappear at an inconvenient moment?
* Licensing or pricing scheme: How will trivial transactions such as pan and zoom count against overall service consumption costs? Can licensing effectively be extended to multiple, concurrent users In computer science, the number of concurrent users for a resource in a location, with the location being a computing network or a single computer, refers to the total number of people using the resource at the same time. within a constrained con·strain
tr.v. con·strained, con·strain·ing, con·strains
1. To compel by physical, moral, or circumstantial force; oblige: felt constrained to object. See Synonyms at force.
2. domain of authorized and authenticated au·then·ti·cate
tr.v. au·then·ti·cat·ed, au·then·ti·cat·ing, au·then·ti·cates
To establish the authenticity of; prove genuine: a specialist who authenticated the antique samovar. users?
* In the case of image services, what image formats are offered (GIF GIF
in full Graphics Interchange Format
Standard computer file format for graphic images. GIF files use data compression to reduce the file size. The original version of the format was developed by CompuServe in 1987. , JPEG JPEG
in full Joint Photographic Experts Group
Standard computer file format for storing graphic images in a compressed form for general use. JPEG images are compressed using a mathematical algorithm. , PNG (Portable Network Graphics) A bitmapped graphics file format endorsed by the World Wide Web Consortium. It is expected to eventually replace the GIF format, because there are lingering legal problems with GIFs. , etc.)?
Service discovery is available through the National Map catalog, Geospatial One-Stop (GOS), and regional services such as NC OneMap, but exhaustive, comprehensive access is still not available. The National Map Catalog covers a subset of the services available in GOS, and GOS covers a subset of all available services. The National Map Catalog exposes an API for application developers, raising the possibility of drawing from these service metadata collections to develop specific local catalogs (USGS, 2005). Other more extensive service catalogs A service catalog, as defined in ITIL Service Delivery, is a list of services that an organization provides, often to its employees or customers. Each service within the catalog typically includes:
NRL (NRL Noun 1. NRL - the United States Navy's defense laboratory that conducts basic and applied research for the Navy in a variety of scientific and technical disciplines
Naval Research Laboratory ) GIDB GIDB Geospatial Information Data Base Portal, which lists nearly 1,400 map servers and over 300,000 individual data layers (Naval Research Laboratory, 2006a), and Mapdex, which lists over 1,700 servers (Mapdex, 2006). The NRL is working on a searchable catalog system that will be compliant with the OGC Catalog Services Specification and will provide the capability to browse, search, and query using any OGC Catalog client application (Naval Research Laboratory, 2006b).
Providing Map Services Another possible library role lies in the area of helping to fill the holes in map service availability by, for example, serving up WMS layers that are not otherwise available. Rather than risk providing stale data that are better provided by the data producers, libraries might focus on serving out specific strategic content that users and other services could choose to consume. NCSU Libraries, for example, is deploying census data map services that will be integrated with the NC OneMap environment, helping to plug a hole in data availability within the statewide framework. Libraries, by virtue of their mission, might be more predisposed pre·dis·pose
v. pre·dis·posed, pre·dis·pos·ing, pre·dis·pos·es
a. To make (someone) inclined to something in advance: than other organizations to serve out lower-demand older or archival content that is not served up by data producers, who may tend to focus on the highest-demand, most current data.
Map Portals and Cascading Map Services Libraries may also have a role to play in deployment of the next-generation version of the old map server: setting up map servers that draw from and build on top of multiple existing map services, thereby creating single map interfaces. The USGS National Map at the national level and NC OneMap at the state level are two prominent examples of cascading map services. In general, one of the things libraries try to do is build windows to the world of information where the window is orientated o·ri·en·tate
v. o·ri·en·tat·ed, o·ri·en·tat·ing, o·ri·en·tates
To orient: "He . . . in a way that best suits the library's client base, often resulting in a particular geographic focus. In the case of map services, this notion might he translated into building specialized views that integrate existing map services.
In practice there are many complicated issues involved with setting up cascading map services: services adhere to adhere to
verb 1. follow, keep, maintain, respect, observe, be true, fulfil, obey, heed, keep to, abide by, be loyal, mind, be constant, be faithful
2. different versions of OGC standards, use different symbolization symbolization /sym·bol·iza·tion/ (sim?bol-i-za´shun) an unconscious defense mechanism in which one idea or object comes to represent another because of similarity or association between them. , apply different scale restrictions, and name their data in different ways (for example, land parcels versus cadastral or property boundaries Ask a Lawyer
Country: United States of America
Land property House built in 1960's. Her house was built her house was built years late. My and myself own our house. ). Also, metadata that is needed to properly integrate resources may be missing, and rights issues concerning services are often ambiguous.
Building an effective cascading map service often becomes an exercise in community building that the technical interoperability specifications do not themselves address. Service builders must work closely with data providers to standardize stan·dard·ize
1. To cause to conform to a standard.
2. To evaluate by comparing with a standard. service characteristics such as symbolization, classification schemes, scale thresholds, and layer naming. The relevant community must agree to and promote a set of practices that go beyond whatever requirements the actual standards or specifications might impose, as has been illustrated in the NC OneMap experience of developing a statewide integrated set of services (NCGICC, 2006c). The reality is that federal and state agencies participating in spatial data infrastructure A Spatial Data Infrastructure or SDI is a framework of spatial data, metadata, users and tools that are interactively connected in order to use spatial data in an efficient and flexible way. are usually better positioned to carry out the community-building process.
Licensing Commercial Web Services Another opportunity for libraries lies in the area of licensing fee-based services for use by patrons. Such services may offer more than just content, with functions such as geocoding and routing being offered by emerging commercial services. Key challenges lie in the area of working out effective licensing models and in integrating campus identification and authorization schemes with these commercial products.
Using Web Services Consumption as a Measure Demand Another possible use of geospatial Web services is in the measurement of data demand associated with a library's user market. Development of digital geospatial data collections that fit the spatial demand footprint of the library's audience can be a challenging task. Funds are limited, and only so much data covering so much territory can be acquired and managed. To the extent that content exists, user demand can be measured based on data downloads by region, but if data holdings do not exist for given areas then demand cannot easily be assessed. It might be possible to carry out more rigorous market analysis if, for example, libraries were able to obtain zoom-in density maps from aggregated data reflecting their institution's traffic on national portals such as Geospatial One-Stop and the National Map.
WEB MASHUPS See mashup. , GEO-HACKING, AND THE NEW GEOSPATIAL FRONTIER
in full Extensible Markup Language.
Markup language developed to be a simplified and more structural version of SGML. It incorporates features of HTML (e.g., hypertext linking), but is designed to overcome some of HTML's limitations. ) and other technologies ("Mashing This article or section contains .
The purpose of Wikipedia is to present facts, not to teach subject matter. the Web," 2005). The explosion during 2005 of creative activity on top of these services is likely to be just the beginning of a revolution in how geospatial content is used and republished.
The geospatial content available in these environments is still limited, with only a very, very small slice of all available geospatial content exposed for use with these systems; however, holes are being poked and then widened through the walls that separate the new commercial Web mapping realm from the much more content-rich traditional GIS realm as developers create tools that integrate WMS or WFS services with Google Maps (Flood, 2005; Mulka, 2005) or convert traditional geospatial data to Keyhole Markup language Keyhole Markup Language (KML) is an XML-based language for describing three-dimensional geospatial data and its display in application programs. KML was developed for use with Google Earth, which was originally named Keyhole. (KML KML Keyhole Markup Language
KML Killing My Lobster (comedy troupe, San Francisco, California)
KML Killing Myself Laughing
KML Knowledge Markup Language
KML Keyed Modeling Language ) for integration with Google Earth (Martin, 2005). The new mainstream mapping space has a very large audience, and yet only a relatively small proportion of available data is exposed to these environments. Meanwhile, in the traditional geospatial industry space there is a relatively small audience and a very large amount of data available. As these two information spaces begin to connect and merge, a number of new opportunities are likely to emerge for libraries.
One very immediate impact of Google Maps, Google Earth, and the like will be the creation of a much larger audience and market for geospatial information resources (1) The data and information assets of an organization, department or unit. See data administration.
(2) Another name for the Information Systems (IS) or Information Technology (IT) department. See IT. . While those doing Web mashups are often commercial information technology developers, they are also often members of the general public developing maps for their churches, schools, or community groups. Mainstream developers crossing over to geospatial systems, while initially naive on the topic of data quality, are developing a more sophisticated understanding of the qualitative differences between data alternatives and are seeking guidance from others in the selection of data sources for integration. One opportunity for libraries will be in the area of exposing archived content to the Web mashup environment for before-and-after and time-related uses, as the emerging services currently focus, for the most part, on delivery of only the most current data.
DIGITAL PRESERVATION CHALLENGES IN THE WEB SERVICES ERA
While the emergence of geospatial Web services has opened up a number of opportunities for libraries, a significant threat is also posed. History has shown that it is quite often secondary archives that preserve content over long periods of time rather than the original content producers. For example, libraries typically preserve books rather than publishers. Until recently, in order to provide efficient access to content it has been necessary to physically acquire the data in order to make it available to users. As a result, data archives have often evolved as a somewhat accidental by-product by·prod·uct or by-prod·uct
1. Something produced in the making of something else.
2. A secondary result; a side effect.
1. of the process of providing access. With the emergence of Web services it will be much easier to point to the data source and avoid handling data and storage media altogether. This is convenient for the user and eases the burden on the library, but who then archives and preserves the data? If preservation of digitally born resources was already a problem before the advent of Web services, the shift to new distribution efforts will require an even more focused and intentional effort on the part of libraries to preserve data.
Many GIS professionals will readily admit that retention of older content is often very low on the list of priorities. "Kill and fill" is often the operating archival strategy. In the early years of GIS it may have made more sense to ignore the temporal component of geospatial data resources: there was little older content so time series analysis was out of the question anyway, barring massive and expensive vector digitizing "Digitizer" redirects here. For the computer device, see Digitizing tablet. For the digitizer in Tablet PC's, see Tablet PC.
Digitizing or digitization of old maps. Most GIS projects are focused on problems that require the use of the most current data. Issues of convenience also undermine demand for older content: the fact that students, during their formative training, will tend to build class projects around available data perhaps reinforces the inclination to focus on more current content and topics.
Yet there is increasing evidence of a rise in demand for older content and of interest in doing associated temporal analysis. GIS has been in use for decades now, so users--especially younger users--are starting to expect that older content will exist. More projects are focusing on time series components--looking backwards at land use change and looking forward at business trends, for example. As GIS becomes more of a core enterprise resource at the local levels, the stakes are raised vis-a-vis accountability for the disposition of taxpayer-funded data development work.
Early Geoarchiving Efforts at NCSU
Geoarchiving is one term that has been used to describe the problem of preserving digital geospatial content (Maine GeoArchives, 2004). In 2000 the coincidence of emerging local agency data, rising user demand for that data, and a growing sense of long-term risk to data sparked an NCSU project targeting county and city data for acquisition and archiving. One learning outcome of that project was a deeper understanding of the complexity of the process of identifying data resource availability across many counties and municipalities. Another learning outcome was an awareness that more efficient and effective data management processes were needed. It was surprisingly easy to turn on the "fire hose" that sent torrents of data into the library collection, but the "plumbing" to deal with all of the content that could be acquired needed to be developed.
The Need for an Infrastructure-Based Approach to Preservation
This early archiving effort made it clear that a statewide infrastructure-based approach was required, one that would build from existing geospatial data infrastructures that were evolving under the auspices of the National Spatial Data Infrastructure National Spatial Data Infrastructure - (NSDI)
http://fgdc.er.usgs.gov/nsdiover.html. (NSDI NSDI - National Spatial Data Infrastructure ), Federal Geographic Data Committee Federal Geographic Data Committee - (FGDC)
ftp://fgdc.er.usgs.gov/gdc/html/fgdc.html. , and Geospatial One-Stop. Two key developments in 2003 helped push NCSU Libraries' preservation effort to the next level: the NC OneMap Initiative and the National Digital Information Infrastructure and Preservation Program The National Digital Information Infrastructure and Preservation Program is a national strategic program being led by the Library of Congress to preserve digital content. The program was mandated in 2000 by the U.S. (NDIIPP NDIIPP National Digital Information Infrastructure Preservation Program (US Library of Congress) ), with its Cooperative Partnership Program.
NC OneMap Initiative In February 2003 the NC OneMap initiative was announced (NCGICC, 2003). NC OneMap is a combined state, federal, and local initiative that is focused on allowing users to view geographic data Geographic data is about much more than electronic pictures of maps.
The geographic data that describes our world allows for city planning, flood prediction and relief, emergency service routing, environmental assessments, wind pattern monitoring and many other applications. seamlessly across North Carolina; search for and download data for use on their own GIS; view and query metadata; and determine who has what data through an online data inventory (NCGICC, 2006b). Included in the NC OneMap vision statement was the assertion that "Historic and temporal data will be maintained and available" (NCGICC, 2003). While primarily focused on access and content standardization standardization
In industry, the development and application of standards that make it possible to manufacture a large volume of interchangeable parts. Standardization may focus on engineering standards, such as properties of materials, fits and tolerances, and drafting , NC OneMap has offered a scalable framework by which the 100 counties and many municipalities in the state might be engaged in the problem of preservation.
NDIIPP In August 2003 the Library of Congress put out a call for proposals in connection with a new congressionally funded initiative focused on preservation of digitally born content: the National Digital Information Infrastructure and Preservation Program. In this first funding round of the program, entitled "Building a Network of Partners: Collaborative Collection Development," the Library of Congress sought to engage with a diverse set of partners in a "dual effort to identify, get, and sustain significant material while also collaborating with the Library and the other partners to advance digital preservation methods and best practices" (Library of Congress, 2003). The eight selected projects address a range of content types, including Web pages, numeric social sciences data, business records, and cultural heritage resources (Library of Congress, 2006). One of the NDIIPP cooperative projects is the NC Geospatial Data Archiving Project (NCGDAP), a partnership between NCSU Libraries, the NC Center for Geographic Information and Analysis, and NC OneMap (NCSU Libraries, 2006b).
NORTH CAROLINA GEOSPATIAL DATA ARCHIVING PROJECT
NCGDAP is focused on collection and preservation of digital geospatial data resources from state and local government agencies in North Carolina. The objectives of NCGDAP include
* identification of available resources through the NC OneMap data inventory;
* acquisition of at-risk geospatial data, including static data such as digital orthophotos as well time series data such as local land records and assessment data;
* development of a digital repository architecture for geospatial data using open source software tools such as Dspace;
* enhancement of existing geospatial metadata with additional preservation metadata using Metadata Encoding See encode. and Transmission Standard (METS METS Metropolitans (New York baseball team)
METS Metadata Encoding and Transmission Standard
MetS Metabolic Syndrome
METS Metabolic Equivalents (multiples of resting oxygen uptake) ) records as wrappers In data mining and treatment learning, wrappers were used by Ron Kohavi and George John. Their idea was to wrap their treatments learners in a preprocessor that would search to make subsets from the current set of attributes. ;
* investigation of automated identification and capture of data resources using emerging Open Geospatial Consortium specifications for client interaction with data on remote servers;
* development of a model for data archiving and time series development.
The project is operating under a three-year timeline from late 2004 to late 2007. Since the project is set within the context of an emerging Web services framework--NC OneMap and the National Map--the project is especially focused on responding to evolving data distribution methods and engaging emerging geospatial Web services in the archive development process.
Although the Web services aspects of the preservation problem are the focus of discussion here, a few salient issues related to the challenge of long-term preservation of digital geospatial data should be highlighted.
Geospatial Data Formats The absence of reliable, open vector formats is a stumbling block stum·bling block
An obstacle or impediment.
any obstacle that prevents something from taking place or progressing
Noun 1. to preservation. SDTS SDTS Spatial Data Transfer Standard
SDTS Self Defense Test Ship
SDTS Spatial Data Transfer Specification
SDTS State Diplomatic Telecommunications System (Spatial Data Transfer Standard Spatial Data Transfer Standard, or SDTS, is a standard used to describe earth-referenced spatial data. It was designed to easily transfer and use spatial data on different computer platforms. ), while open, has proven problematic and is not in wide use. The initial plan of the NCGDAP project involves retention of the data objects in the format received, while also exporting the content into a safer commercial vector format and buying time until a reliable, open alternative emerges. It is considered preferable to retain the content in a widely understood and supported commercial format rather than to rely solely on a migration of the content to an open format that may not be widely supported and conversion to which may involve subjecting the content to some unfortunate transformations and data loss.
One thread of investigation involves the use of Geography Markup Language The Geography Markup Language (GML) is the XML grammar defined by the Open Geospatial Consortium (OGC) to express geographical features. GML serves as a modeling language for geographic systems as well as an open interchange format for geographic transactions on the Internet. (GML GML Geography Markup Language (XML components for encoding geospatial data)
GML Greek Mythology Link (website)
GML Generalized Markup Language ) in an archival capacity. The challenge with this approach is that GML is not really a format per se but rather a means to define something akin to formats in the form of GML profiles and GML application schemas Geography Markup Language provides the basis for domain- or community-specific "Application Schemas", which in turn support data interoperability within a community of interest. Application schemas are normally designed using ISO 19103 conformant UML, and then the GML Application created (Lake, 2005). The emerging Simple Features Profile for GML provides a potential solution in the form of a widely supported GML profile that is more sustainable over time, though quality and functionality tradeoffs against industry-specific GML application schemas will be a consideration (OGC, 2005a). NCGDAP will be participating in a broader effort by the National Archives National Archives, official depository for records of the U.S. federal government, established in 1934 by an act of Congress. Although displeasure concerning the method of keeping national records was voiced in Congress as early as 1810, the United States continued and Records Administration (NARA Nara (nä`rä), city (1990 pop. 349,349), capital of Nara prefecture, S Honshu, Japan. An ancient cultural and religious center, it was founded in 706 by imperial decree and was modeled after Chang'an (see Xi'an), the capital of T'ang China. ) and the Federal Geographic Data Committee (FGDC FGDC - Federal Geographic Data Committee ) Historical Data Working Group to investigate the role of GML in preservation (FGDC, 2006).
Another area of investigation concerns mining of data inventories, possibly using the emerging RAMONA system being developed by the National States Geographic Information Council (Indiana GIC GIC
See: Guaranteed Investment Contract
See guaranteed investment contract (GIC). , 2006), to detect format "doppler signals" using a format's loss of market share as a possible indicator of format risk.
Geospatial Databases Another problem is the widespread emergence of complex spatial databases A spatial database is a database that is optimized to store and query data related to objects in space, including points, lines and polygons. While typical databases can understand various numeric and character types of data, additional functionality needs to be added for databases , either of the commercial variety or in more open varieties such as PostGIS-based systems. A spatial database stores geographic features and attributes as objects hosted inside a relational database management system relational database management system - relational database . Multiple data layers may be stored in a single database, which may also host elements such as topology topology, branch of mathematics, formerly known as analysis situs, that studies patterns of geometric figures involving position and relative position without regard to size. , relationships, behaviors, and annotations that are not exportable to conventional vector file formats. Within the project domain, the ESRI Geodatabase format is a prominent example of this approach to data management. Until recently spatial databases were relatively rare in the project domain, but local agencies--especially municipalities--are increasingly turning to the ESRI Geodatabase format in particular to manage geospatial data (NCGICC, 2004).
Preserving Cartographic car·tog·ra·phy
The art or technique of making maps or charts.
[French cartographie : carte, map (from Old French, from Latin charta, carta, paper made from papyrus Representation The true counterpart to the old, preserved map is not the current GIS dataset but rather the cartographic representation that builds on that data. The representation is the result of a collection of intellectual choices and application of current methods with regard to symbolization, classification, data modeling, and annotation 1. (programming, compiler) annotation - Extra information associated with a particular point in a document or program. Annotations may be added either by a compiler or by the programmer. . One goal of capturing cartographic representation will be to preserve data in the form that decision makers and others encountered and interpreted it. Another goal, in the case of image capture approaches, would be to provide a stable, preservation-friendly--though "dumbed down"--alternative in the case of long-term failure in the vector data preservation process. The derived image might also serve as a content preview, helping fixture researchers decide whether to commit time and resources to do whatever "digital archeology" (Ross & Gow, 1999) might be necessary to resurrect the underlying content. Any preservation of cartographic representation should, ideally, occur in addition to preserving the underlying data.
In the Web services context, one issue to consider is that decisions will increasingly be made on the basis of ephemeral maps created online, making it difficult to document the basis for decisions. The OGC Web Map Context specification addresses the issue of saving the application state in order to re-create maps but does not address the issue of saving data state (OGC, 2005b).
Time-Versioned Content Many of the vector data layers to be acquired are subject to frequent update. County cadastral (land parcel) datasets, for example, are typically updated on a daily or weekly basis. Such time-versioned content, if preserved, can form the basis of time series analyses such as land use change analysis.
Version-handling over time, however, can be quite difficult to manage within the archive. And experience in the content domain has shown that some resources of only a few years of age have already lived in two or three repository environments, so any single repository cannot be expected to have all of the versions.
Content Packaging One of the points of frustration in working with geospatial content in a library context has been the absence of a packaging or bundling scheme for data. Geospatial data is characterized by complex multifile formats that need to be tied together, bundling data with associated metadata and ancillary documentation. Content packaging mechanisms may be used to bundle different versions of the dataset (by format, coordinate system, tiling scheme, etc.), to attach rights information and licensing, to supplement FGDC metadata with additional technical and administrative metadata, and to link objects with services that act upon them. The NCGDAP project will experiment with the use of the Metadata Encoding and Transmission Standard, a technology that has emerged in the library community, as a data bundling scheme. Other packaging schemes, such as the MPEG (Moving Pictures Experts Group) An ISO/ITU standard for compressing digital video. Pronounced "em-peg," it is the universal standard for digital terrestrial, cable and satellite TV, DVDs and digital video recorders (DVRs). 21 Digital Item Declaration Language Digital Item Declaration Language (DIDL) is an XML dialect standardized in MPEG-21. It is used by devices implementing the Universal Plug and Play (UPnP) AV standard. , are being considered in connection with the OGC Geo Digital Rights Management (GeoDRM) initiative (OGC, 2006).
Other Geoarchiving Challenges Other preservation challenges include securing and adequately defining archival and use rights for content; preserving semantic information associated with datasets; providing long-term support of coordinate systems and datums; and maintaining the independence of the preserved content from any particular repository software environment.
Putting Web Services to Work in Geoarchiving
While the shift toward Web services--based distribution of geospatial data may pose a threat to long-term preservation of content, it is also possible that those same geospatial Web services might in the future aid in the onerous process of developing archives on the basis of widely distributed Adj. 1. widely distributed - growing or occurring in many parts of the world; "a cosmopolitan herb"; "cosmopolitan in distribution"
bionomics, environmental science, ecology - the branch of biology concerned with the relations between organisms sources. Taking the example of North Carolina alone, there are 100 counties and over 140 municipalities. Nearly all North Carolina counties have GIS systems, as do many municipalities. Keeping track of data availability across this many agencies is not a trivial problem. Even more problematic is the task of routinely harvesting content from such a diversity of agencies.
In this context Web services become interesting from the point of view of automating inventory creation and automating extract and transfer of content. One of the difficult selling points selling point
An aspect of a product or service that is stressed in advertising or marketing.
Noun 1. selling point - a characteristic of something that is up for sale that makes it attractive to potential customers for digital preservation has been the level of effort that must be applied to solve a problem that is very low on the list of priorities of data producers. If the process of archive development can be automated using Web services, then the barrier to participation in the preservation process might be lowered considerably.
Unfortunately, currently deployed services based on OGC specifications are not really fashioned to the needs of archive development processes. In terms of data transfer, WMS involves transfer of "dumb" images with the data intelligence removed. Web Feature Service (WFS), which involves transfer of the actual data as GML, is perhaps not really optimized for full-scale transfer of entire datasets or databases (OGC, 2005c). Furthermore, WFS is not yet widely deployed. What is lacking, so far, is a sort of rsync-like layer in the spatial data infrastructure that allows for efficient, full-scale replication of data resources while also being informed by data update processes, rights arrangements, and metadata. In cases where delta files--or change files--are used as a means of transferring database changes across the network, archival processes will need to handle conflation (database) conflation - Combining or blending of two or more versions of a text; confusion or mixing up. Conflation algorithms are used in databases. of the delta files with the archived database and certify that no delta files have been missed.
Geospatial Web services, which may be image services, feature services, geocoding services, or offer other functionality, are clearly on the rise. These new, dynamic resources are more useful for some applications than others, where access to static resources will continue to be more suitable. These services are notably difficult to discover, creating opportunities for libraries in the area of facilitating discovery of and access to them. The rise of more mainstream map services such as Google Maps, through its API, appears to be leading toward a rapid growth in the use of geospatial data and services by a broader audience.
At the same time, digital geospatial data is becoming increasingly ephemeral. The challenges in preserving static geospatial data are already daunting daunt
tr.v. daunt·ed, daunt·ing, daunts
To abate the courage of; discourage. See Synonyms at dismay.
[Middle English daunten, from Old French danter, from Latin as we face the issue of preserving proprietary formats and spatial databases, capturing time series snapshots, and preserving cartographic representation. The advent of geospatial Web services raises additional challenges to data preservation, as static files are replaced by dynamic, changing services. At the same time, new Web services technologies may offer some possibility of making the process of archive development more efficient through the use of automated approaches.
Doyle, A. (2000). Web mapping testbed. Retrieved February 24, 2006, from http://www.intlinterfaces.com/wmt2/wms.html.
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1. The study or interpretation of symbols or symbolism.
2. The use of symbols.
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Steve Morris Steve 'Slippery' Morris was an Australian rugby League footballer.
A halfback, Morris played for the Dapto club. In the 1978 season he gained selection in the New South Wales Country Rugby League side and was then chosen to represent Australia, making Morris the last player is Head of Digital Library Initiatives Digital Library Initiative - A project to research digital libraries which aims to provide real collections to real users (high school students, University researchers and students, users in public libraries). as North Carolina State University (NCSU) Libraries and has worked for the past dozen years in the area of facilitating access to geospatial data. He is principal investigator Noun 1. principal investigator - the scientist in charge of an experiment or research project
scientist - a person with advanced knowledge of one or more sciences in a partnership with the Library of Congress focusing on preservation of digital geospatial data. Steve has a master's degrees master's degree
An academic degree conferred by a college or university upon those who complete at least one year of prescribed study beyond the bachelor's degree.
Noun 1. in both geography and library and information studies.