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1.
《制图学和地理信息科学》2013,40(5):315-320
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. 相似文献
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《制图学和地理信息科学》2013,40(5):294-295
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. 相似文献
3.
《制图学和地理信息科学》2013,40(5):306-310
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). 相似文献
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《制图学和地理信息科学》2013,40(3):176-178
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. 相似文献
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《制图学和地理信息科学》2013,40(5):311-314
A processor to support the Spatial Data Transfer Standard (NIST 1992) is being designed. The Spatial Data Transfer Processor will support both encoding and decoding operations. The system will have five components: transfer manager, content encoder, format encoder, content decoder, and format decoder. No component will have expertise in more than one area. The system design should be used as a guide when developing software for the SDTS. NOTE: Readers should be familiar with mapping concepts described in the article “An Implementation Strategy for SDTS Encoding,” located elsewhere in this issue. 相似文献
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《制图学和地理信息科学》2013,40(3):180-189
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. 相似文献
8.
《制图学和地理信息科学》2013,40(5):300-302
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. 相似文献
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《制图学和地理信息科学》2013,40(5):296-299
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. 相似文献
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《制图学和地理信息科学》2013,40(5):321-327
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. 相似文献
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《制图学和地理信息科学》2013,40(5):332-334
Dramatic changes in the way that spatial data have been collected and processed over that last 20 years is leading to a rethinking and restructuring on the most efficient ways to handle geographical information. These changes are taking place at the federal, state, and local governmental levels with great potential for the private sector as well. The formal adoption of the Spatial Data Transfer Standard (SDTS) as the federal database transfer standard for spatial databases signals a new era in this long chain of developments. It offers more flexible and efficient database transfers than earlier tools, and will become the workhorse for implementing the new National Spatial Data Infrastructure. It offers organizations a standard that will make possible and practical a much wider sharing of databases than is currently being done today. Use of the SDTS presents an opportunity to many organizations to share data more easily and reduce the duplication of expensive spatial database resources. 相似文献
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《制图学和地理信息科学》2013,40(3):172-175
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. 相似文献
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《制图学和地理信息科学》2013,40(3):150-154
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. 相似文献
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《制图学和地理信息科学》2013,40(3):132-135
The concept of a framework for data and information linkages among producers and users, known as a National Spatial Data Infrastructure (NSDI), is built upon four corners: data, technology, institutions, and standards. Standards are paramount to increase the efficiency and effectiveness of the NSDI. Historically, data standards and specifications have been developed with a very limited scope — they were parochial, and even competitive in nature, and promoted the sharing of data and information within only a small community at the expense of more open sharing across many communities. Today, an approach is needed to grow and evolve standards to support open systems and provide consistency and uniformity among data producers. There are several significant ongoing activities in geospatial data standards: transfer or exchange, metadata, and data content. In addition, standards in other areas are under discussion, including data quality, data models, and data collection. 相似文献
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《制图学和地理信息科学》2013,40(3):136-139
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. 相似文献
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《制图学和地理信息科学》2013,40(4):359-367
Common Spatial Data Models (SDMs) such the vector, raster, and quadtree have well understood and widely practiced conventions of storage and visualization. This paper explores what happens when the conventions of visualization are not strictly adhered to, and the SDMs are used in an atypical fashion. A framework based on a quasi similarity measure is presented, which quantifies (in terms of "distance") the relationship between the storage format and the visualization output, following an accepted protocol. This research used a transformation process (Tp) to define this distance. Then, the atypical use of the quadtree SDM to represent choropleth spatial boundary uncertainty and attribute uncertainty was quantified using the same framework. This research shows that if a SDM is used outside of its original context, then the distance between the storage format and its visual output can alter; in our case, the distance decreased. This result was interpreted as evidence for the creation of a new spatial data structure. The formalization of the relationship between an SDM and its visual output will be valuable for future exploration of the non-conventional visualization of common SDMs. 相似文献
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《制图学和地理信息科学》2013,40(5):328-331
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. 相似文献
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《制图学和地理信息科学》2013,40(1):25-35
Previously, we developed an integrated software package called ICAMS (Image Characterization and Modeling System) to provide specialized spatial analytical functions for interpreting remote sensing data. This paper evaluates three fractal dimension measurement methods that have been implemented in ICAMS: isarithm, variogram, and a modified version of triangular prism. To provide insights into how the fractal methods compare with conventional spatial techniques in measuring landscape complexity, the performance of two spatial autocorrelation methods, Moran's I and Geary's C, is also evaluated. Results from analyzing 25 simulated surfaces having known fractal dimensions show that both the isarithm and triangular prism methods can accurately measure a range of fractal surfaces. The triangular prism method is most accurate at estimating the fractal dimension of surfaces having higher spatial complexity, but it is sensitive to contrast stretching. The variogram method is a comparatively poor estimator for all surfaces, particularly those with high fractal dimensions. As with the fractal techniques, spatial autocorrelation techniques have been found to be useful for measuring complex images, but not images with low dimensionality. Fractal measurement methods, as well as spatial autocorrelation techniques, can be applied directly to unclassified images and could serve as a tool for change detection and data mining. 相似文献
19.
《制图学和地理信息科学》2013,40(1):42-50
Geographic Information Systems (GIS) algorithms are used to simplify, edge match, and overlay large data sets. Some of these GIS processes can cause considerable positional changes to spatial data which are sometimes difficult to assess. This study presents a visualization technique for the evaluation of GIS algorithms and their positional effects on spatial data. The technique is applicable to vector representations and can be used with any GIS operation that changes vector geometry. The technique employs a uniform reference grid to exploit the visual skills of human operators in the evaluation of positional changes in spatial databases after applying GIS transformations. Changes in grid cell length, area, and shape, along with a set of displacement vectors, can be analyzed to evaluate positional changes in spatial data and to compare the behaviors of different algorithms. The technique can assist GIS users in the documentation of positional changes and in the comparison and selection of algorithms for various mapping tasks. Such a technique may assist software developers in creating and selecting appropriate GIS algorithms. 相似文献
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