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For Prototype Use Only

National Mapping Division

U.S. Geological Survey

Last updated on 10/29/93.

Document Point of Contact:

This document was written by Phyllis Altheide of the Software Engineering Section of the Branch of Research , Technology, and Applications, located at the Mid-Continent Mapping Center in Rolla, Missouri. Please send comments or questions to palth@usgs.gov.

This document can be obtained from an anonymous FTP site at sdts.er.usgs.gov. It is available in PostScript or WordPerfect 5.1 format.

Preface

The purpose of this document is to describe how the DLG-E Model maps into the Spatial Data Transfer Standard. This document is written from the perspective of the DLG-E Model. The terminology and concepts are those of DLG-E unless specifically stated to be of the SDTS. The DLG-E model is briefly described to aid in the comprehension of the mapping. A familiarity with the concepts and structures of the SDTS and the Topological Vector Profile is assumed.

The mapping described herein conforms to the Topological Vector Profile implementation (7/6/93) of the SDTS. The mapping herein should be considered a prototype mapping and subject to change for two major reason: 1) there are many options in mapping to the SDTS, and 2) the NMD's DLG-E is not yet a well-defined and stable product. The most likely to change will be the feature attribute table designs as content requirements are still evolving for the DLG-E product. The DLG-E content used within this document is based on version 0.12 of the NMD DLG-E Content Standards Database (DSDB), and the December 1992 design of the DLG-E Portable Data File (DPDF).

The document is divided into three parts. Part 1 describes the DLG-E model, Part 2 the mapping of it into the SDTS/TVP, and Part 3 the E/SDTS transfer and the DLG-E Data Dictionary transfer.

Part 1 contains Sections 1-2. Section 1 describes the DLG-E model. Section 2 describes the USGS/NMD implementation of the DLG-E. Part 2 contains Sections 3-7. Section 3 describes the mapping of the spatial objects. Section 4 describes the mapping of the other objects of the DLG-E model: dataset, theme, surface, and feature. Sections 5 and 6 describe the mapping of the DLG-E attribute model. Section 7 describes the mapping of the DLG-E relationships. Part 3 contains Sections 8-9. Section 8 describes the DLG-E/SDTS transfer. Section 9 describes the DLG-E Master Data Dictionary Transfer.

Appendix A describes the results of the feature attribute table design in Section 6. Appendix B lists the attributes from the DSDB that are encoded as SDTS attributes. Appendix C lists the attributes from the DPDF that are encoded as SDTS attributes. Appendix D contains an example set of SDTS modules illustrating a DLG-E encoding of feature attributes and relationships.

To other users of the SDTS who may use this document as a case study:

The work generating the information contained in this document followed the implementation strategy as described in the article "An Implementation Strategy for SDTS Encoding", Cartography and Geographic Information Systems, 12/92.

References:

FIPS PUB 173: Spatial Data Transfer Standard (August 28, 1992). Available from The National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22161. Text online at Anonymous FTP site sdts.er.usgs.gov, directory "standard"

Part 4: Topological Vector Profile (July 6, 1993) Available from The National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22161. Text online at Anonymous FTP site sdts.er.usgs.gov, directory "standard"

Cartography and Geographic Information Systems, Vol 19, No. 5, December 1992, American Congress on Surveying and Mapping, Special Issue on SDTS. Text of some articles online at Anonymous FTP site sdts.er.usgs.gov, directory "articles"

USGS Circular 1048: Digital Line Graph -Enhanced [Historical background]. Available from U.S. Geological Survey, National Center, Reston, VA 22092.

SDTS Software and Datasets. For the latest available, see Anonymous FTP site sdts.er.usgs.gov, directory "software" and "datasets".

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