Implementation of the Spatial Data Transfer Standard in the Commonwealth of Virginia

Present efforts to implement the Spatial Data Transfer Standard (SDTS) within the Commonwealth of Virginia are centered in Virginia's Council on Information Management (CIM). Since 1992, mapping, surveying and land information systems activities have been identified as a responsibility of the Council "The promotion of access to federal and other digital data banks through standards" is an area of CIM interest specified in the Code of Virginia. Prior to adoption of the SDTS by Virginia in November 1994, a Technical Advisory on the SDTS was issued and a SDTS Training and Education Plan was adopted. The Council on Information Management has worked with the USGS SDTS Task Force in developing this plan.     

The Spatial Data Transfer Standard: A Catalyst for Change

The Spatial Data Transfer Standard (SOTS), as a standard, is somewhat of a paradox. Standards help to establish order and promote stability. As such, SDTS serves both as a standard and a catalyst for change. Beyond being the first major geographic information systems(GIS) standard, SOTS has invoked—and continues to invoke—significant changes throughout federal organizations and other' organizations that interact with them. The changes inspired by SDTS focus attention on the importance of GIS standards. This importance, in turn, is the underlying force in creating a GIS standards infrastructure. The infrastructure provides a mechanism/process for developing, approving, and coordinating GIS standards in the federal, national, and international communities.     

An SDTS Implementation for GRASS

Developers of the Geographic Resources Analysis Support System (GRASS) at the U.S. Army Corps of Engineering Research Laboratories (USACERL) have been closely involved with the SDTS project since February 1992. Software for the exchange of data between GRASS and SDTS is near completion. Access to SDTS data via this software promises many benefits for GRASS users, but SDTS will also pose challenges to the GRASS user community just as it has for the creation of GRASS-SDTS software itself. Areas of difficulty include distinctions between SDTS and GRASS in the definition of certain spatial objects, SDTS metadata requirements, and accommodation within GRASS of the complex data attribute schemas that will be typical of SDTS data sets.     

Profile Development for the Spatial Data Transfer Standard

The Spatial Data Transfer Standard (SDTS), or Federal Information Processing Standard (FIPS) 173, is designed to support all types of spatial data. Implementing all of the standard's options at one time is impractical. Therefore, implementation of the SDTS is being accomplished through the use of profiles. Profiles are clearly defined, limited subsets of the SDTS created for use with a specific type or model of data and designed with as few options as possible. When a profile is proposed, specific choices are made for encoding possibilities that were not addressed, left optional, or left with numerous choices within the SDTS. Profile development is coordinated by the U.S. Geological SUIVey's SDTS Task Force. When completed, profiles are submitted to the National Institute of Standards and Technology (NIST) for approval as official amendments to the SDTS. The first profile, the Topological Vector Profile (TVP), has been completed. A Raster Profile has been tested and is being finalized for submission to the NIST. Other vector profiles, such as those for network and nontopological data, are also being considered as future implementation options for the SDTS.     

Developing a Raster Profile for the Spatial Data Transfer Standard

The Spatial Data Transfer Standard (SDTS) was designed to transfer both vector and raster data sets. In the early development of the SDTS, the designers recognized that there was a need to transfer raster data in addition to the more challenging vector data. As a result, the SDTS includes a “raster module” that accommodates a variety of raster data structures and formats. A raster profile is being developed that will exercise a selected subset of SDTS capabilities in order to provide a simple-to-use transfer of complete raster data sets.     

Continuing Research Needs Resulting from the SDTS Development Effort

For more than a decade, efforts to develop and specify the U.S. Spatial Data Transfer Standard (SDTS) have on many occasions encountered limitations in both theory and "gaps in our knowledge" which have hindered its development. This work examines broad categories of these limitations from the perspective of research needs, to encourage further research on these topics. Areas in need of further study include fundamental concepts, the specification and use of spatial objects, spatial data quality, entity definitions, the data transfer mechanism, and international comparison of transfer mechanisms. In many cases recent research progress has been made in these areas and this progress is pointed out. A number of high-priority research areas are identified. It is hoped that this work will encourage more research effort to be directed towards these areas, which will benefit not only the development of spatial data transfer standards but also the spatial data sciences in general.     

Cartography/Geographic Information Systems at Southwest Texas State University

Australia and New Zealand are adopting the Spatial Data Transfer Standard (SDTS) as their transfer standard for geographic data. The standard requires a number of modifications to suit Australia/New Zealand requirements. These modifications primarily involve coordinate reference systems for each country, references to those standards applicable to each country and new spatial feature dictionaries. For other countries adopting SDTS, future revisions to the standard should emphasize a framework for required modifications. Australia/New Zealand have established a support body to ensure the smooth introduction of the standard within these countries. This commercial venture has been successful in promoting the standard, in providing training and in related consulting work. The US Geological Survey has been the maintenance authority for the standard. It is essential that this function continues to be provided through this body to guarantee a single interpretation of the standard.     

Conversion of a U.S. Geological Survey DLG-3 Data Set to the SDTS Topological Vector Profile

The Digital Line Graph level 3 (DLG-3) is the term for U.S. Geological Survey digital spatial data stored in vector form. Prior to the approval of the Spatial Data Transfer Standard (SDTS) as a Federal Information Processing Standard (FIPS), a system was developed to convert a DLG-3 data set to a sample SDTS transfer. The specifications of the SDTS Topological Vector Profile were used for the transfer (U.S. Geological Survey 1992). The process required expertise in cartography, geography, and computer science. Analysis revealed requirements for processes to transform spatial addresses, to translate and map DLG-3 spatial objects and attribute pairs to the SDTS, to compile data not available in computer-readable form, and to convert files to FIPS 123 (ISO 8211) standard. Mapping data to the SDTS proved to be complex and highlighted the need for appropriate training with regard to the SDTS and FIPS 123. Several issues were raised, such as the source of data quality information, platforms supported by the FIPS 123 Function Library software, and attribute translation criteria.     

The SDTS Topological Vector Profile

Because the Spatial Data Transfer Standard (SDTS), also Federal Information Processing Standard 173, is designed to support any type of spatial data, implementing all of its options at one time is impossible. Instead, the SDTS is implemented through the use of profiles, which are limited subsets of the SDTS. The first profile developed is the Topological Vector Profile. This profile supports geographic vector data with geometry and topology. It does not support raster data, graphic representation modules, and geometry-only vector data. This profile was tested in 1992 in order to validate it. It will be submitted to the National Institute of Standards and Technology as an amendment to the SDTS.     

An Implementation Strategy for SDTS Encoding

Any implementation plan for the Spatial Data Transfer Standard (NIST 1992) must include the following minimum set of tasks: conceptual, logical, and format level mappings; verification of the mappings; and systems development. These tasks are used as a guide in formulating specific project plans. For a data producer to implement an encoding capability, the tasks are learning the SDTS, conceptual mapping, module mapping, building sample modules, format mapping, encoding a sample data set, and developing the system. NOTE: This article assumes familiarity with the SDTS constructs of modules, fields, and subfields and the relationship of the SDTS to ISO 8211 (American National Standards Institute 1986).     

An Overview of FIPS 173, The Spatial Data Transfer Standard

The Spatial Data Transfer Standard (SDTS), after nine years of development, was approved on July 29, 1992, as FIPS Publication 173. The SDTS consists of three distinct parts. Part 1 is concerned with logical specifications required for spatial data transfer and has three major components: a conceptual model of spatial data, data quality report specifications, and detailed logical transfer format specifications for SDTS data sets. Part 2 provides a model for the definition of real-world spatial features, attributes, and attribute values and includes a standard but working and expandable list with definitions. Part 3 specifies the byte-level format implementation of the logical specifications in SDTS Part 1 using ISO/ANSI 8211 (FIPS 123), a general data exchange standard.     

The Spatial Data Transfer Standard (FIPS 173): A Management Perspective

The Spatial Data Transfer Standard (SDTS) was approved by the Department of Commerce as Federal Information Processing Standard (FIPS) 173 on July 29, 1992. As a FIPS, the SDTS will serve as the national spatial data transfer mechanism for all federal agencies and will be available for use by state and local governments, the private sector, and research organizations. FIPS 173 will transfer digital spatial data sets between different computer systems, making data sharing practicable. This standard is of significant interest to users and producers of digital spatial data because of the potential for increased access to and sharing of spatial data, the reduction of information loss in data exchange, the elimination of the duplication of data acquisition, and the increase in the quality and integrity of spatial data. The success of FIPS 173 will depend on its acceptance by users of spatial data and by vendors of spatial information systems. Comprehensive workshops are being conducted, and the tools and procedures necessary to support FIPS 173 implementations are being developed. The U.S. Geological Survey, as the FIPS 173 maintenance authority, is committed to involving the spatial data community in various activities to promote acceptance of FIPS 173 and to providing case examples of prototype FIPS 173 implementations. Only by participating in these activities will the members of the spatial data community understand the role and impact of this standard.     

TIGER/SDTS Topology

The Census Bureau is committed to using the Spatial Data Transfer Standard (SDTS) and is developing an extract from the Census TIGER? called the TIGER/SDTS?. A single file of the prototype TIGER/SDTS is now available with which interested data users may experiment. This paper will graphically describe some of the SDTS concepts and census geographic concepts used in the TIGER/SDTS. The Census TIGER? and the TIGER/SDTS? are trademarks of the Bureau of the Census.     

TIGER/SDTS: Standardizing an Innovation

The explosion of computer processing capabilities for manipulating geographic data has produced a concomitant increase in the number of geographic data file formats available. The many formats make it difficult to exchange and manipulate geographic data from several sources, and sometimes even from the same source. The U.S. Bureau of the Census has been a contributor to the “Yet Another Geographic File Format” movement over the past two decades with its Address Coding Guides (following the 1970 decennial census), the GBF/DIME-Files (following the 1980 decennial census), and four different versions of its TIGER/Line files at various times during the 1990 decennial census cycle. The TIGER data base is a massive computer file that provides geographic information about the entire United States and its territories in great detail, down to the individual city block and its component boundary features. Its value to more than Census Bureau activities is enormous. To enhance the value of the TIGER data base, and to make it easier to use, the Census Bureau is releasing the file in the new Spatial Data Transfer Standard (SDTS) format. The benefits of a standard transfer format are manifold. This paper discusses some of the intergovernmental activities that were required before the exchange standard was adopted and some of the problems of implementing the standard within the Census Bureau. The Census Bureau is not alone in its decision to release geographic data files in the SDTS format, and some of the benefits of using the standard for exchanging data among agencies also are described.     

A Spatial Data Infrastructure Approach for the Characterization of New Zealand's Groundwater Systems

The future information needs of stakeholders for hydrogeological and hydro‐climate data management and assessment in New Zealand may be met with an Open Geospatial Consortium (OGC) standards‐compliant publicly accessible web services framework which aims to provide integrated use of groundwater information and environmental observation data in general. The stages of the framework development described in this article are search and discovery as well as data collection and access with (meta)data services, which are developed in a community process. The concept and prototype implementation of OGC‐compliant web services for groundwater and hydro‐climate data include demonstration data services that present multiple distributed datasets of environmental observations. The results also iterate over the stakeholder community process and the refined profile of OGC services for environmental observation data sharing within the New Zealand Spatial Data Infrastructure (SDI) landscape, including datasets from the National Groundwater Monitoring Program and the New Zealand Climate Database along with datasets from affiliated regional councils at regional‐ and sub‐regional scales. With the definition of the New Zealand observation data profile we show that current state‐of‐the‐art standards do not necessarily need to be improved, but that the community has to agree upon how to use these standards in an iterative process.     

GridGNSS--网格化全球卫星导航系统

计算机网络技术的发展已经使全球的信息资源实现网络互联和页面浏览,新一代的基于IPv6的IP地址方案的实施,将可以满足全球几乎任意的资源连接互联网的需要。随着移动通讯技术的发展,移动互联网和移动IP技术可以使移动用户通过网络实现全球资源的互联和访问。因此,对于通过全球卫星定位系统进行移动目标定位的用户,可以通过移动网络的方式实现传统的数据传输和通讯。随着新一代互联网络的的发展,WebService成为全球信息发布的最主要的平台,基于WebService的GNSS综合信息发布可以实现全球GNSS资源和信息的访问,计算机网格的出现为全球GNSS计算提供技术支持,本文基于网格技术,提出了GNSS网格和GridGNSS的概念,对GridGNSS的功能和研究内容进行了详细分析,并对GridGNSS的实现过程和应用进行了阐述。     

Spatio-temporal evaluation matrices for geospatial data

The global geospatial community is investing substantial effort in providing tools for geospatial data-quality information analysis and systematizing the criteria for geospatial data quality. The importance of these activities is increasing, especially in the last decade, which has witnessed an enormous expansion of geospatial data use in general and especially among mass users. Although geospatial data producers are striving to define and present data-quality standards to users and users increasingly need to assess the fitness for use of the data, the success of these activities is still far from what is expected or required. As a consequence, neglect or misunderstanding of data quality among users results in misuse or risks. This paper presents an aid in spatio-temporal quality evaluation through the use of spatio-temporal evaluation matrices (STEM) and the index of spatio-temporal anticipations (INSTANT) matrices. With the help of these two simple tools, geospatial data producers can systematically categorize and visualize the granularity of their spatio-temporal data, and users can present their requirements in the same way using business intelligence principles and a Web 2.0 approach. The basic principles and some examples are presented in the paper, and potential further applied research activities are briefly described.     

GEOCAB Portal: A gateway for discovering and accessing capacity building resources in Earth Observation

The discovery of and access to capacity building resources are often essential to conduct environmental projects based on Earth Observation (EO) resources, whether they are Earth Observation products, methodological tools, techniques, organizations that impart training in these techniques or even projects that have shown practical achievements. Recognizing this opportunity and need, the European Commission through two FP7 projects jointly with the Group on Earth Observations (GEO) teamed up with the Committee on Earth observation Satellites (CEOS). The Global Earth Observation CApacity Building (GEOCAB) portal aims at compiling all current capacity building efforts on the use of EO data for societal benefits into an easily updateable and user-friendly portal. GEOCAB offers a faceted search to improve user discovery experience with a fully interactive world map with all inventoried projects and activities. This paper focuses on the conceptual framework used to implement the underlying platform. An ISO19115 metadata model associated with a terminological repository are the core elements that provide a semantic search application and an interoperable discovery service. The organization and the contribution of different user communities to ensure the management and the update of the content of GEOCAB are addressed.     

Residential area evaluation using GIS technique: A case study — Part of Bhubaneswar city

To evaluate a planning area or to implement plan procedures, planners need database in the form of land use, population density, housing density and point information regarding various facilities. At present planning tasks are carried out by manual methods where analytical capabilities are limited. Therefore, there is a need for reliable data as well as comprehensive database information indicating physical factors and good analytical tools. In a development plan various standards are specified in zoning regulations for the development of a city. To get an overall view, how these standards are implemented on the ground in planning period, a GIS application can be useful in analysing various amenity standards with respect to population and distances. In this study, for part of Bhubaneswar, basic data was generated from 1988 aerial photographs and other related information was gathered through field survey and secondary sources. The derived information in the form of a map has been entered into computer through digitization. Vector information was later converted into a raster form for the analysis. As per the planning standards catchment areas were created for limited facilities/services like schools, parks, play ground and accessibility to bus stop from main road. The population actually served by these facilities were calculated and compared with the existing planning standards. This particular study demonstrates the use of GIS in one of the planning tasks especially analyzing the residential areas as per the set standards such that improvement schemes can be proposed accordingly in the deficient areas.