FGDC Document Number

1 1 FGDC Document Number XX2 3 4National Shoreline Data Content Standard 5Working Draft 6 7 8Marine and Coastal Spatial Data Subcommittee 9Federal Geographic Data Committee 10 11January 2007 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 342______3 _Federal Geographic Data Committee 4 Department of Agriculture • Department of Commerce • Department of Defense • Department of Energy 5 Department of Housing and Urban Development • Department of the Interior • Department of State 6 Department of Transportation • Environmental Protection Agency 7 Federal Emergency Management Agency • Library of Congress 8 National Aeronautics and Space Administration • National Archives and Records Administration 9 Tennessee Valley Authority 35Federal Geographic Data Committee 36 37Established by Office of Management and Budget Circular A-16, the Federal Geographic 38Data Committee (FGDC) promotes the coordinated development, use, sharing, and 39dissemination of geographic data. 40 41The FGDC is composed of representatives from the Departments of Agriculture, 42Commerce, Defense, Energy, Housing and Urban Development, the Interior, State, and 43Transportation; the Environmental Protection Agency; the Federal Emergency 44Management Agency; the Library of Congress; the National Aeronautics and Space 45Administration; the National Archives and Records Administration; and the Tennessee 46Valley Authority. Additional Federal agencies participate on FGDC subcommittees and 47working groups. The Department of the Interior chairs the committee. 48 49FGDC subcommittees work on issues related to data categories coordinated under the 50circular. Subcommittees establish and implement standards for data content, quality, and 51transfer; encourage the exchange of information and the transfer of data; and organize the 52collection of geographic data to reduce duplication of effort. Working groups are 53established for issues that transcend data categories. 54 55For more information about the committee, or to be added to the committee's newsletter 56mailing list, please contact: 57 58 Federal Geographic Data Committee Secretariat 59 c/o U.S. Geological Survey 60 590 National Center 61 Reston, Virginia 22092 62 63 Telephone: (703) 648-5514 64 Facsimile: (703) 648-5755 65 Internet (electronic mail): [email protected] 66 World Wide Web: http://www.fgdc.gov 6710 ii 11 68CONTENTS 69Page 701. Introduction...... 1 71 1.1 Objective and Justification...... 1 72 1.2 Scope...... 3 73 1.4 Applicability and Intended Uses of the Standard...... 3 74 1.5 Relationship to Related Standards...... 3 75 1.6 Standards Development Procedures...... 4 76 1.6.1 Participants...... 5 77 1.7 Maintenance Authority...... 7 782. Rationale for Design...... 7 79 2.1 National Shoreline...... 7 80 2.2 Design of the Data Content Standard...... 8 81 2.2.1 Shoreline Parent Table Elements...... 9 823. Data Model...... 13 83 Figure 1...... 13 844. Entities and Attributes Definitions...... 14 855. REFERENCES...... 22 866. APPENDICES...... 23 87 6.1 Informative Appendix...... 23 88 6.1.1 Informative Appendix 1: Tidal_Type_Domain...... 23 89 6.1.2 Informative Appendix 2: Horizontal Datum Domain...... 27 90 6.1.3 Informative Appendix 3: Shoreline_Definition_Domain...... 28 91 6.1.4 Informative Appendix 4: Boundary_Reference_Domain...... 29 92 6.1.5 Informative Appendix 5: Legal Status Domain...... 32 93 6.1.6 Informative Appendix 6: Source Type Domain...... 33 94 6.1.7 Informative Appendix 7: Classification System Domain...... 34 95 6.1.8 Informative Appendix 8: Ellipsoidal_Type_Domain...... 35 96 6.1.9 Informative Appendix 9: Orthometric_Type_Domain...... 35 97 9812______13 _Federal Geographic Data Committee 14 Department of Agriculture • Department of Commerce • Department of Defense • Department of Energy 15 Department of Housing and Urban Development • Department of the Interior • Department of State 16 Department of Transportation • Environmental Protection Agency 17 Federal Emergency Management Agency • Library of Congress 18 National Aeronautics and Space Administration • National Archives and Records Administration 19 Tennessee Valley Authority 20Federal Geographic Data Committee FGDC Document Number XX 21National Shoreline Data Content Standard, Committee Review Draft, January 2007 22______991. Introduction 1001011.1 Objective and Justification 102 103 The location of our national shoreline is a baseline for legal boundaries, nautical104charts, and commercial and natural resource utilization and management. Effective use105of shoreline data requires a highly defined logical data structure that is interoperable,106efficient and applicable to a broad base of government and private sector demands.107Current practices have led to a highly variable shoreline data infrastructure. In108accordance with Executive Order 12906, and subsequent Executive Order 13286 an109amendment to E.O. 12906, initiatives for geospatial data standardization is underway.110Domestically, Federal Geographic Data Committee (FGDC) and the American National111Standards Institute (ANSI) along with international organizations i.e. Internal112Organization for Standardization (ISO) are catalysts for the development of geospatial113standards. As a result, FGDC-STD-001.2.-2001, Shoreline Metadata Profile of the114Content Standard for Digital Geospatial Metadata was developed. The National115Shoreline Data Content Standard is intended to enhance the shoreline framework by116providing technical guidance on shoreline semantics, data structures and their117relationships to builders and users of shoreline data.118 Shoreline definition protocols currently limit agencies and organizations from119effectively sharing and using shoreline coincident data. Agencies have expressed an120interest for greater harmonization and uniformity to shoreline data content. Enhancing121shoreline content and interoperability is technically feasible and timely in relation to122hydrographic, hydrologic and other related standards development. The proposed23 iv 24Federal Geographic Data Committee FGDC Document Number XX 25National Shoreline Data Content Standard, Committee Review Draft, January 2007 26______123standard shall tie related protocols and existing content together in a new model using124recognized reference material, definitions, semantics, and structures. Harmonizing125shoreline content will lead to cost savings by reducing the time in design, data re-use,126training, and implementation. In addition, harmonizing shoreline data content assists in127areas as coastal research, historical shoreline change analysis, shoreline change prediction128analysis, and the effects of relative sea rise. The National Shoreline Data Content129Standard provides a framework for shoreline data development, sharing of data, and130shoreline data transformation and fusion. The standard defines attributes or elements that131are common for shoreline data development. The standard provides suggested domains132for the elements including a reference to the Shoreline Metadata Profile of the Content133Standard for Digital Geospatial Metadata.134 Relative to data transformation and fusion, the common framework reference for135shoreline data supports the recommendation of the Coastal States Organization136mentioned on page 51 of “A Geospatial Framework for the Coastal Zone” by the137National Research Council of the National Academies:138 139 “.. that the USACE together with NOAA, FEMA, USGS, and other appropriate 140 agencies should be tasked to ‘identify, compile, integrate and make available to 141 the states data and information on shoreline change and process, and work in 142 conjunction with states and other local project sponsors to identify further 143 information and data collection processes needed to fill the gaps in understanding 144 a comprehensive approach to littoral system management’ (CSO 2002; pp 19-20)” 145146 Per project example, the United States Geological Survey is undertaking the task 147of developing the National Map http://nationalmap.gov/. This project is an example of 148the requirement for a common set base information. A common framework to support 27 v 28Federal Geographic Data Committee FGDC Document Number XX 29National Shoreline Data Content Standard, Committee Review Draft, January 2007 30______149data fusion and data partners specific to shoreline as the National Resource Council states150above.1511.2 Scope 152 153 The geographical scope of the standard comprises all shorelines within the coastal154and inland waterways for the United States, its Commonwealths, and Territories and any155other possession that the United States exercises sovereignty.156The functional scope of the standard includes the definition of data models, schemas,157entities, relationships, definitions, and cross-walks to related standards. Legal158controversy has historically surrounded shoreline definitions because of the boundary159implications. This standard will provide a framework inclusive of multiple shoreline160interpretations, and will not attempt to resolve disputed terminology. Data discovery,161transmittal, display, and delivery are not currently part of this standard.162 1631.4 Applicability and Intended Uses of the Standard 164 165 Mapping, shoreline engineering, coastal zone management, flood insurance, and166the natural resource management communities are the primary audience of this standard.167The standard is intended to support the shoreline community in developing shoreline data168to support data transformation, data fusion, and data sharing.169 The standard is not reflective of an implementation design, though one is170provided as an example. An implementation or application design should, however,171incorporate the concepts found in this standard.31 vi 32Federal Geographic Data Committee FGDC Document Number XX 33National Shoreline Data Content Standard, Committee Review Draft, January 2007 34______1721.5 Relationship to Related Standards 173 174 Numerous logical relationships exist between the proposed standard and other175standards currently published or are in development. Shoreline features are currently part176of several standards providing reference to a specific shoreline definition. This standard,177The National Shoreline Data Content Standard provides information that encompasses178shoreline variables and elements in greater detail and extent than the following standards:179 180  Content Standard for Digital Geospatial Metadata (version 2.0), FGDC-STD-001- 181 1998 182  Content Standards for Framework Land Elevation Data, March 21, 2005, standard 183 is at FGDC Step 9. Document date January 2000. 184  IHO Transfer Standard for Digital Hydrographic Data (S-57) 185  Cadastral Data Content Standard, FGDC-STD-003, 3rd Revision, May 2003 186  Geographic Information Framework Data Content Standards for Hydrography 187 (ANSI) 188 189190 The Metadata Profile for Shoreline Data, FGDC-STD-001.2-2001, has a direct191relationship to the National Shoreline Data Content Standard. The profile preceded the192content standard. The intent of the metadata profile was a first attempt to provide193shoreline developers with a framework in describing processes, tools, and techniques for194creating geospatial shoreline data. As a result of the metadata profile being the sole195source for shoreline data descriptors, feature attribution lacked the coherence and196congruence due to geospatial shoreline data variability which resulted in the call for197developing The National Shoreline Data Content Standard. 198199 With the endorsement and adoption of the National Shoreline Data Content Standard200by FGDC and shoreline constituents, the metadata profile will naturally undergo a35 vii 36Federal Geographic Data Committee FGDC Document Number XX 37National Shoreline Data Content Standard, Committee Review Draft, January 2007 38______201process of examination and redevelopment. Redevelopment of the metadata profile will202follow the current FGDC maintenance procedures as stated in the Metadata Profile for203Shoreline Data.2041.6 Standards Development Procedures 205 206 This standard followed the guidelines as prescribed by the FGDC, and was207overseen by the FGDC Marine and Coastal Spatial Data Subcommittee. The standard208development and modeling advisory team directed the project on a daily basis and209reported to Captain Brian K. Taggart, NOAA, as the primary sponsor. Additional210direction was provided by subscribers, contributors, and reviewers in their roles as211defined in FGDC guidelines. List serve, email, teleconference and web based212communications were used to reach a broad constituency. Project team meetings were213scheduled on an as needed basis depending on available resources. 214 Special attention was focused on evaluating the relationship of the proposed215standard to the current Metadata Profile for Shoreline Data, FGDC-STD-001.2-2001.216The Metadata Profile contains valuable references related to the proposed standard, and is217a result of an early and possibly premature effort to develop a shoreline data content218standard. A recommendation will be presented to the Standards Working Group during219the development process for modifying or harmonizing with the Metadata Profile for220Shoreline Data.2211.6.1 Participants 222 A Call for Participation was forwarded via e-mail to shoreline constituents223nationwide. The levels of participation, as described in the Call for Participation, are224presented below. 39 viii 40Federal Geographic Data Committee FGDC Document Number XX 41National Shoreline Data Content Standard, Committee Review Draft, January 2007 42______225 Standards Development and Modeling Advisory Team: Members who will be226 tasked with developing content definitions, assisting modelers, writing, and227 editing the Standard. This is the group of people who will be the most active228 participants in the process. A 6 month time period has been planned for the229 development of the National Shoreline Data Content Standard Working Draft. 230 Reviewer: Interested in reviewing various drafts of the Standard when ready.231 Reviewers will have a time requirement of up to 2 weeks depending on the review232 demands of the individual standard effort. 233 Contributor: Interested in offering model input, background information to be234 considered in design. The Contributor role will not require significant time235 commitments. However individuals who agree to this role will be expected to236 provide timely information when requested. 237 Subscriber: Interested in listening and staying informed about progress of the238 Standards Development and Modeling Advisory Team. The Subscriber role will239 not require significant time commitments. However individuals who agree to this240 role will be expected to provide timely information when requested.241 The list below is of individuals who have contributed to the development of the242standard. 243 Name Agency Henry Norris Florida Marine Research Institute Bruce Potter Island Resource Foundation Karen J. Gray NGA Adam Bailey NGA Dennis Walker NGA43 ix 44Federal Geographic Data Committee FGDC Document Number XX 45National Shoreline Data Content Standard, Committee Review Draft, January 2007 46______Robert Wilson NOAA Greg Fromm NOAA Dave Stein NOAA Kimberly Owens NOAA Mike Brown NOAA Mike Rink NOAA Jeffrey Lillycorp USACE Jeff Williams USGS Richard Naito MMS 244245 The National Shoreline Data Content Standard Development and Modeling246Advisory team was assisted by Daniel Martin and chaired by William E. Linzey, both of247Perot Systems Government Services. For further information regarding the standard visit248the web page http://www.fgdc.gov/standards/projects/FGDC-standards-249projects/shoreline-data-content/index_html2502511.7 Maintenance Authority 252 253 The U.S. Department of Commence, National Oceanic and Atmospheric254Administration (NOAA), National Ocean Service (NOS), National Geodetic Survey255(NGS) will maintain the National Shoreline Data Content Standard. Maintenance256guidelines of the National Shoreline Data Content Standard will follow the FGDC257guidance as described by Directive #9 “Maintenance and Support”. Address questions258concerning this standard to:259 260 NOAA, National Geodetic Survey 261 1315 EAST WEST HWY 262 SILVER SPRING MD 20910-3282 263 [email protected] 264 26547 x 48Federal Geographic Data Committee FGDC Document Number XX 49National Shoreline Data Content Standard, Committee Review Draft, January 2007 50______2662. Rationale for Design 2672682.1 National Shoreline269 Transparent to technological methodologies, the National Shoreline Data Content270Standard entails the development of a common data framework that enables shoreline271developers and users to readily share, transform, and fuse shoreline data.272273 The concept of a National Shoreline Data Content Standard is paramount in274supporting shoreline data development and user activities. This concept is principal to275shoreline due to the variety of shoreline definitions, domestic and international legal276implications, methods of data capture, and lack of interoperable shoreline data among277local, State, and Federal entities. The existing variety of shoreline data structures278provides an impediment towards the fusion of data in support of modeling tools.279280 Shoreline data users require shoreline delineation at a various precisions, in both281the horizontal and vertical datum to support a variety of project purposes. Data modeling282activities such as the V-Datum tool provide an effort towards developing seamless283topography to hydrography data, essentially a seamless “land to sea floor” data set. 284285 With the absence of a referencing document (a content standard) providing for a286common framework for shoreline data, efforts such as data transformation and data287fusion would prove to be laborious due to the incongruence of shoreline data. The288National Shoreline Data Content Standard resolves the issue surrounding incongruence51 xi 52Federal Geographic Data Committee FGDC Document Number XX 53National Shoreline Data Content Standard, Committee Review Draft, January 2007 54______289by creating a vehicle which provides for a common framework standard for shoreline290data development. 2912922.2 Design of the Data Content Standard 293 294 On Page seven of the FGDC March 1996 “Standards Reference Model” it states;295“Data content standards provide semantic definitions of a set of objects …” In essence, a296data content standard is a finite set of information that communicates an essential set of297elements for and at a feature level. The effort or premise in designing the National298Shoreline Data Content Standard is to create an empirical form or format that represented299shoreline geospatial data. This format is viewed as the common denominators required300when developing shoreline data that promotes data integrity and cohesiveness in support301of data development, data sharing, and data fusing. The derived model accounts for and302incorporates aspects of the Shoreline Metadata Profile of the Content Standard for Digital303Geospatial Metadata, FGDC-STD-001.2-2001. As a result, the FGDC endorsement of304this standard provides the opportunity to update and enhance the Shoreline Metadata305Profile of the Content Standard for Digital Geospatial Metadata, FGDC-STD-001.2-2001.306307 The elements considered to be essential or primary in shoreline data are found in308the Shoreline_Parent content. (see diagram in Section 3 Data Model). These elements309were found to be the foundation or a common framework for shoreline geospatial data310that will facilitate data sharing, transformation, and fusion. 31155 xii 56Federal Geographic Data Committee FGDC Document Number XX 57National Shoreline Data Content Standard, Committee Review Draft, January 2007 58______312 Although the underpinnings for the content are found in the Shoreline_Parent313table, the elements providing expanded content are found in the support element tables,314see diagram in Section 3 Data Model. The support content describes further the parent315content elements by expanding on the set of entry variables for shoreline data. 3163172.2.1 Shoreline Parent Table Elements 318 319Vertical_Datum 320 321Code lists provide for referencing of the three classes of vertical datum: 322 323  Tidal describes a datum that is affected by the tidal epoch. Datum that were and 324 are derived for rivers, lakes, and oceans are included in this domain. 325 326  Orthometric describes a datum that is essentially equipotential surfaces of the earth 327 tied to one or more tide stations as control points. North American Vertical Datum 328 1988, NAVD88 is one example 329 330  Ellipsoidal describes a datum that is based on a geometric model of the earth, an 331 ellipsoid. WGS84, World Geodetic System is an example of an ellipsoidal datum 332 333334Horizontal_Datum335Provides a reference for the entry of the horizontal datum. A look up table lists examples336of horizontal datum is provided.337338Date339Provides for the calendar date entry of the original shoreline data capture. 340341Time342Provides for the time of day of the original shoreline data capture.59 xiii 60Federal Geographic Data Committee FGDC Document Number XX 61National Shoreline Data Content Standard, Committee Review Draft, January 2007 62______343344Shoreline_Definition345Provides for existing shoreline definitions to be referenced in the development of346shoreline data. This element will not establish the definition of shoreline, however, the347standard recognizes the variety of shoreline definitions relative to the variety of purposes348of shoreline data.349350NSSDA_H_Value351Provides for the entry of the National Standard for Spatial Data Accuracy, FGDC-STD-352007.3-1998, tested horizontal value from the statement of conformance under the353Accuracy Reporting section.354NSSDA_V_Value355Provides for the entry of the National Standard for Spatial Data Accuracy, FGDC-STD-356007.3-1998, tested vertical value from the statement of conformance under the Accuracy357Reporting section.358359Source_Type and Source_ID360Provides information regarding the source or sources in developing shoreline data. 361362Geometry_ID 363Provides information regarding the location system utilized. The information provided in364this table can be found in the Contents Standard for Digital Geospatial Metadata, FGDC-365STD-001-1998 section 4. 63 xiv 64Federal Geographic Data Committee FGDC Document Number XX 65National Shoreline Data Content Standard, Committee Review Draft, January 2007 66______366367Classification_ID368Provides for the entry of a shore area that exists at the time and date of shoreline data369capture. A variety of classifications can be used, such as the Environmental Sensitivity370Index (ESI) to classify this predominant shore area. Shoreline classification schemes are371numerous in which the Classification_ID lists the known, at the time this standard was372written, shoreline classifications. A shoreline geospatial data developer is encouraged to373not only classify the shoreline but to identify the source of the classification being used.374375Record_Boundary376The Cadastral Data Content Standard, FGDC-STD-003, 3rd Revision, May 2003 provides377the attribution and suggested domain for this entry and is listed in the standard.67 xv 68Federal Geographic Data Committee FGDC Document Number XX 69National Shoreline Data Content Standard, Committee Review Draft, January 2007 70______3783. Data Model379Figure 1380 38171 xvi 72Federal Geographic Data Committee FGDC Document Number XX 73National Shoreline Data Content Standard, Committee Review Draft, January 2007 74______3824. Entities and Attributes Definitions 383 384 The entity and attribute diagram in Section 3.0, Data Model, provides an385illustration of the National Shoreline Data Content Standard.386387 The informative annexes provides lists of domain values that can be used during388implementation of the standard. Where applicable, references and explanations of the389elements in the domains are provided for further clarification and explanation. It is390suggested during implementation, that null or void values not be entered, rather, where391applicable, the use of not applicable or unknown for that entity or the actual value of the392entity be entered. 393394Vertical_Datum395 For marine applications, a base used as a reference from which to reckon heights396 or depths. It is called a tidal datum when defined in terms of a certain phase of397 the tide. Tidal datums are local datum and should not be extended into areas398 which have differing hydrographic characteristics with substantiating399 measurements. In order that they may be recovered when needed, such datums400 are referenced to fixed points known as bench marks (Hicks,2000)401 Tidal402 Elevation_Value403 Numeric entry expression for a value identifying positive, above404 the shoreline plane of reference, and negative, below the plane of405 reference. 75 xvii 76Federal Geographic Data Committee FGDC Document Number XX 77National Shoreline Data Content Standard, Committee Review Draft, January 2007 78______406407 Epoch408 Also known as phase lag. Angular retardation of the maximum of a409 constituent of the observed tide (or tidal current) behind the corresponding410 maximum of the same constituent of the theoretical equilibrium tide. It411 may also be defined as the phase difference between a tidal constituent412 and its equilibrium argument. As referred to the local equilibrium413 argument, its symbol is k. When referred to the corresponding Greenwich414 equilibrium argument, it is called the Greenwich epoch and ids415 represented by G. A Greenwich epoch that has been modified to adjust to416 a particulate time meridian for convenience in the prediction of tides is417 represented by g or by k’. The relations between these epochs may be418 expressed by the following formula:419 G = k + pL 420 g = k’ = G – aS / 15 421 in which L is the longitude of the place and S is the longitude of the time422 meridian, these being taken as positive for west longitude and negative for423 east longitude; p is the number of constituent periods in the constituent424 day and is equal to 0 for all long-period constituents, 1 for diurnal425 constituents, 2 for semidiurnal constituents, and so forth; and a is the426 hourly speed of the constituent, all angular measurements being expressed427 in degrees. (2) As used in tidal datum determination, it is the 19 year cycle428 over which tidal height observations are meaned in order to establish the429 various datums. As there are periodic and apparent secular trends in sea79 xviii 80Federal Geographic Data Committee FGDC Document Number XX 81National Shoreline Data Content Standard, Committee Review Draft, January 2007 82______430 level, a specific 19 year cycle (the National Tidal Datum Epoch) is431 selected so that all tidal datum determinations throughout the United432 States, its territories, Commonwealth of Puerto Rico, and Trust Territory433 of the Pacific Islands, will have a common reference. (Hicks, 2000) 434435 Tidal_Type436 Any of the entries in the Tidal_Type_Domain, including tidal437 datum not listed and described by “other” in the table are to use438 this entry.439 Orthometric440441 Orthometric_Height442 The distance between the geoid and a point, measured along the vertical443 through the point and taken positive upward from the geoid. Also called444 orthometric elevation. Orthometric heights are used in topographic445 mapping.446 Geoid_Model447 “A mathematical model that describes the surface of a geoid based upon a448 geodetic datum and associated reference ellipsoid. The geoid model is449 defined using a set of spherical harmonic coefficients or an implemented450 set of algorithms in a computer program.” 451 http://www.august.com/epicentre/local/geoid_model.html452 Benchmark83 xix 84Federal Geographic Data Committee FGDC Document Number XX 85National Shoreline Data Content Standard, Committee Review Draft, January 2007 86______453 A fixed physical object or mark used as reference for a horizontal 454 or vertical datum. A tidal bench mark is one near a tide station to 455 which the tide staff and tidal datums are referred. A primary bench 456 mark is the principal mark of a group of tidal bench marks to 457 which the tide staff and tidal datums are referred. The standard 458 tidal bench mark of the National Ocean Service is a brass, bronze, 459 or aluminum alloy disk 3-½ inches in diameter containing the 460 inscription NATIONAL OCEAN SERVICE together with other 461 individual identifying information. A geodetic bench mark 462 identifies a surveyed point in the National Spatial Reference 463 System. Most geodetic bench mark disks contain the inscription 464 VERTICAL CONTROL MARK NATIONAL GEODETIC 465 SURVEY with other individual identifying information. 466 Benchmark disks of either type may, on occasion, serve 467 simultaneously to reference both tidal and geodetic datums. 468 Numerous bench marks of predecessor organizations to NOS, or 469 parts of other organizations absorbed into NOS, still bear the 470 inscriptions: U.S. COAST & GEODETIC SURVEY, NATIONAL 471 GEODETIC SURVEY, NATIONAL OCEAN SURVEY, U.S. 472 LAKE SURVEY, CORPS OF ENGINEERS, and U.S. 473 ENGINEER OFFICE. (Hicks 2000) 474475 Orthometric_Type476 Any of the entries in the Orthometric_Type_Domain, including477 “other” in the table are used for Orthometric types not listed in this478 domain.479 Ellipsoidal480 In geometric terms, a closed surface of which all planar sections are481 ellipses. In general framework, GIS, and mapping practices, an ellipsoid is482 a specific mathematical representation of the earth that more closely483 approximates the shape of the surface than a sphere does.484 Ellipsoidal_Height485 The distance between the ellipsoid and a point, measured along the486 vertical through the point and taken positive upward from the ellipsoid.87 xx 88Federal Geographic Data Committee FGDC Document Number XX 89National Shoreline Data Content Standard, Committee Review Draft, January 2007 90______487 Also called orthometric elevation. Orthometric heights are used in488 topographic mapping.489 Geoid_Model490 “A mathematical model that describes the surface of a geoid based upon a491 geodetic datum and associated reference ellipsoid. The geoid model is492 defined using a set of spherical harmonic coefficients or an implemented493 set of algorithms in a computer program.” 494 http://www.august.com/epicentre/local/geoid_model.html495496 Benchmark497 See Orthometric Bench Mark.498Ellipsoidal_Type499 Any of the entries in the Ellipsoidal_Type_Domain, including500 “other” in the table are used for Ellipsoidal types not listed in this501 domain.502Horizontal_Datum 503 A geodetic reference point that is the basis for horizontal control surveys and504 consists of five quantities: latitude, longitude, the azimuth of a line from the505 reference point, and two constants that are the parameters of the reference506 ellipsoid. The datum may extend over an area of any size. 507508 Horizontal_Datum_Domain91 xxi 92Federal Geographic Data Committee FGDC Document Number XX 93National Shoreline Data Content Standard, Committee Review Draft, January 2007 94______509 Provides a list of datum that may be used for the identification of the510 horizontal datum in use. Though there are numerous horizontal datum in511 use, the table provides examples of datum that are used.512513514Date515 Provides for the calendar date entry of the original shoreline data capture. In an516 implementation model, the reference to date representations in the Content517 Standard for Digital Geospatial Metadata, FGDC-STD-001.1998, is suggested.518519Time520 Provides for the time of day of the original shoreline data capture. In an521 implementation model, the reference to time representations in the Content522 Standard for Digital Geospatial Metadata, FGDC-STD-001.1998, is suggested.523524Shoreline_Definition525 The content lists provides shoreline definitions in which three definitions are cited526 below. Though there are many legal and non-legal definitions for shoreline, data527 developers are encouraged to provide the definition used for shoreline data.528 Shoreline (coastline) – The intersection of the land with the water surface. The 529 shoreline shown on charts represent the line of contact between the land a 530 selected water elevation. In areas affected by tidal fluctuations, this line of531 contact is the mean high water line. In confined coastal waters of diminished tidal95 xxii 96Federal Geographic Data Committee FGDC Document Number XX 97National Shoreline Data Content Standard, Committee Review Draft, January 2007 98______532 influence, the man water level line may be used. (Hicks 2000)533534 Shoreline - The line of contact between the land and a body of water. On Coast535 and Geodetic Survey nautical charts and surveys the shoreline approximates the536 mean high water line. In Coast Survey usage the term is considered synonymous537 with coastline. (Shalowitz, 1964)538539 Shorelines - General term including tidelands and navigable freshwater shores540 below the ordinary high water mark (Coastal States Organization 1997)541542NSSDA_H_Value543Provides for the entry of the National Standard for Spatial Data Accuracy, FGDC-STD-544007.3-1998, tested value from the statement of conformance under the Accuracy545Reporting section.546547NSSDA_V_Value548Provides for the entry of the National Standard for Spatial Data Accuracy, FGDC-STD-549007.3-1998, tested value from the statement of conformance under the Accuracy550Reporting section.551552Source_Type553 Provides for the definition of the source.554 Source_ID99 xxiii 100Federal Geographic Data Committee FGDC Document Number XX 101National Shoreline Data Content Standard, Committee Review Draft, January 2007 102______555 Provides for the specific identification of the source data. This instance,556 the Source_ID can be utilized in an application model.557Geometry_ID558 Provides for the expression of horizontal, x and y, and the vertical, z, for feature559 coordinates including the Coordinate_Reference.560 Coordinate_Reference_ID561 Describes the coordinate system the coordinates represent. 562 Geographic563 The quantities of latitude and longitude which define the position564 of a point on the Earth's surface with respect to a reference565 spheroid.566567 Planar568 A two-dimensional measurement system that locates features on a569 map based on their distance from an origin (0, 0) along two axes, a570 horizontal x-axis representing east–west and a vertical y-axis571 representing north–south.572573 Map_Projection574 The systematic representation of all or part of the surface of the575 Earth on a plane or developable surface.576577Classification 103 xxiv 104Federal Geographic Data Committee FGDC Document Number XX 105National Shoreline Data Content Standard, Committee Review Draft, January 2007 106______578 Classification provides an entry for the description of the shore area. Exposed579 rocky shore, an example of shore area classification, is from page 12 of the580 NOAA Technical Memorandum NOS OR&R 11 Environmental Sensitivity Index581 Guidelines version 3.0. There is, to date, no one shoreline classification standard582 therefore citing the source of the classification utilized is recommended.583 Classification_ID584 Shoreline Classification name for the shore area described.585 Classification_System586 Cite the schema utilized when providing the classification of the shoreline,587 ex, “NOAA Technical Memorandum NOS OR&R 11 Environmental588 Sensitivity Index Guidelines version 3.0”589590Record_Boundary_ID591 Record_Boundary592 Boundary_Reference_Domain593 Legal_Status_Domain594595 The Cadastral Data Content Standard provides the attribution and suggested596domain for this entry of the element Record_Boundary_ID and the associated tables,597Record_Boundary, Boundary_Reference_Domain and Legal_Status_Domain. See598Cadastral Data Content for the National Spatial Data Infrastructure; version 1.3 – Third599Revision May 2003.600107 xxv 108Federal Geographic Data Committee FGDC Document Number XX 109National Shoreline Data Content Standard, Committee Review Draft, January 2007 110______6015. REFERENCES 602 603FGDC, 1998, Content Standard for Digital Geospatial Metadata, Version 2.0, 604Washington, D.C. 605 606FGDC, June 2001, Shoreline Metadata Profile of the Content Standards for Geospatial 607Metadata, Washington, D.C. 608 609FGDC, May 2003, Cadastral Data Content Standard for the National Spatial Data 610Infrastructure, version 1.3 –Third Revision, Washington, D.C. 611 612ANSI, April 3, 2003, Geographic Information Framework Data Content Standards for 613Hydrography (Draft), Information Washington, D.C. 614 615ANSI, September 2003, Geographic Information Framework - For Geodetic Control, 616Washington, D.C. 617 618ANSI, Geographic Information Framework – For Transportation Networks: Roads, 619Washington, D.C. 620 621U.S. Department of Commerce, National Oceanic and Atmospheric Administration, 622(NOAA) April 1, 1988, “National Shoreline Data Standard, Progress Report and 623Preliminary Draft Standard”, Silver Spring, Maryland 624 625U.S. Department of Commerce, National Oceanic and Atmospheric Administration, 626(NOAA), January 2000, “Tide and Current Glossary / [by Steacy D. Hicks ... [et al.].”, 627Silver Spring, Maryland. 628 629National Research Council of the National Academies, 2004, “A Geospatial Framework 630for the Coastal Zone – National Needs for Coastal and Mapping and Charting”, 631Washington, D.C. 632 633Journal of Coastal Research, Special Issue #38, Fall 2003, “Shoreline Mapping and 634Change Analysis: Technical Considerations and Management Implications:, West Palm 635Beach Florida. 636 637U.S. Department of Commerce, National Oceanic and Atmospheric Administration, 6382000, “Shore and Sea Boundaries, the development of International Maritime Boundary 639Principles through United States Practice”, Volume 3, Washington D.C. 640 641Black’s Law Dictionary – Definitions of the Terms and Phrases of American and English 642Jurisprudence, Ancient and Modern, 1982 5th Edition, St. Paul Minnesota, West 643Publishing Company 644 645Boundary Control and Legal Principles, 3rd edition, 1986, Brown, M. Curtis, Robillard, 646Walter G., Wilson, Donald A.; Wiley Interscience Publications111 xxvi 112Federal Geographic Data Committee FGDC Document Number XX 113National Shoreline Data Content Standard, Committee Review Draft, January 2007 114______6476. APPENDICES 6486496.1 Informative Appendix6506.1.1 Informative Appendix 1: Tidal_Type_Domain 651652Chart Datum – The datum to which soundings on a chart are referred. It is usually taken653 to correspond to a low-water elevation, and its depression below mean sea654 level is represented by the symbol Z0. Since 1980, chart datum has been655 implemented to mean lower low water for all main waters of the United656 States, its territories, Commonwealth of Puerto Rico, and Trust Territory657 of the Pacific Islands. (Hicks 2000)659Lowest Astronomical Tide – As defined by the International Hydrographic Organization, 660 the lowest tide level that can be predicted to occur under average meteorological661 conditions and under a combination of astronomical conditions. (Hicks 2000)662663Mean Sea Level – A tidal datum. The arithmetic mean of hourly heights observed over 664 the National Tidal Datum Epoch. Shorter series are specified in the name; e.g.,665 monthly mean sea level and yearly mean sea level. (Hicks 2000)666667Mean Low Water Springs – A tidal datum. Frequently abbreviated spring low water. The668 arithmetic mean of the low water heights occurring at the time of spring tide669 observed over the National Tidal Datum Epoch. It is usually derived by taking an670 elevation depressed below the half tide level by an amount equal to one-half the115 xxvii 116Federal Geographic Data Committee FGDC Document Number XX 117National Shoreline Data Content Standard, Committee Review Draft, January 2007 118______671 spring range of tide, necessary corrections being applied to reduce the result to a672 mean value. This datum is used, to a considerable extent, for hydrographic work673 outside of the United States and is the level of reference for the Pacific674 approaches for the Panama Canal. (Hicks 2000)675676Spring Tides or Tidal Currents – Tides of decreased range or tidal currents of decreased677 speed occurring semimonthly as the result of the Moon being in quadrature. The678 neap range (Np) of the tide is the average range occurring at the time of neap tides679 and is most conveniently computed from the harmonic constants. It is smaller680 than the mean range where the type of tide is either semidiurnal or mixed and is of681 no practical significance where the type of tide is predominantly diurnal. The682 average height of the high waters of the neap tide is called neap high water or683 high water neaps (MHWN) and the average height of the corresponding low684 waters is called neap low water or low water neaps (MLWN). (Tide and Current685 Glossay 2000)686687Neap Tides or Tidal Currents – Tides of decreased range or tidal currents of decreased 688 speed occurring semimonthly as the result of the Moon being in quadrature. The 689 neap range (Np) of the tide is the average range occurring at the time of neap tides690 and is most conveniently computed from the harmonic constants. It is smaller 691 than the mean range where the type of tide is either semidiurnal or mixed and is of692 no practical significance where the type of tide is predominantly diurnal. The 693 average height of the high waters of the neap tide is called neap high water or 119 xxviii 120Federal Geographic Data Committee FGDC Document Number XX 121National Shoreline Data Content Standard, Committee Review Draft, January 2007 122______694 high water neaps (MHWN) and the average height of the corresponding low 695 waters is called neap low water or low water neaps (MLWN). (Tide and Currents 696 Glossary, 2000)697698Mean Diurnal Tide Level – (MDTL) A tidal Datum. The arithmetic mean of the mean 699 higher high water and the mean low lower water (Hicks, 1984)700701Mean High Water – A tidal datum. The average of all the high water heights observed 702 over the National Tidal Datum Epoch. For stations with shorter series,703 comparison of simultaneous observations with a control tide station is made in704 order to derive the equivalent datum of the National Tidal Datum Epoch. (Hicks705 2000)706707Mean Higher High Water – A tidal datum. The average of the higher high water height 708 of each tidal day observed over the National Tidal Datum Epoch. For stations709 with shorter series, comparison of simultaneous observations with a control tide710 station is made in order to derive the equivalent datum of the National Tidal711 Datum Epoch. (Hicks 2000)712713Mean Low Water – A tidal datum. The average of all the low water heights observed 714 over the National Tidal Datum Epoch. For stations with shorter series,715 comparison of simultaneous observations with control tide station is made in123 xxix 124Federal Geographic Data Committee FGDC Document Number XX 125National Shoreline Data Content Standard, Committee Review Draft, January 2007 126______716 order to derive the equivalent datum of the National Tidal Datum Epoch. (Hicks717 2000)718719Mean Lower Low Water – A tidal datum. The average of all low water heights observed 720 over the National Tidal Datum Epoch. For stations with shorter series,721 comparison of simultaneous observations with a control tide station is made in722 order to derive the equivalent datum of the National Tidal Datum Epoch. (Hicks723 2000)724725Gulf Coast Low Water Datum line – The line on a chart or map which represents the 726 intersection of the land with the water surface at the elevation of Gulf Coast Low727 Water Datum. (Hicks 2000)728729Other – tidal datums not described or defined in this domain.7306.1.2 Informative Appendix 2: Horizontal Datum Domain 731732North American Datum of 1983733 The North American Datum of 1927 (NAD 27) is "The horizontal control datum 734 for the United States that (was) defined by (a) location and azimuth on the Clarke 735 spheroid of 1866, with origin at (the survey station) Meades Ranch." ... The 736 geoidal height at Meades Ranch (was) assumed to be zero. "Geodetic positions on 737 the North American Datum of 1927 were derived from the (coordinates of and an 738 azimuth at Meades Ranch) through a readjustment of the triangulation of the 739 entire network in which Laplace azimuths were introduced, and the Bowie 740 method was used." (Geodetic Glossary, pp. 57) 741 The North American Datum of 1983 (NAD 83) is "The horizontal control datum 742 for the United States, Canada, Mexico, and Central America, based on a 743 geocentric origin and the Geodetic Reference System 1980. 127 xxx 128Federal Geographic Data Committee FGDC Document Number XX 129National Shoreline Data Content Standard, Committee Review Draft, January 2007 130______744 "This datum, designated as NAD 83, is the new geodetic reference system. ... 745 NAD 83 is based on the adjustment of 250,000 points including 600 satellite 746 Doppler stations which constrain the system to a geocentric origin." (Geodetic 747 Glossary, pp 57) 748 749North American Datum of 1927750 See North American Datum of 1983751Old Hawaiian752 The Geodetic Datum which is defined by the following geographic position and753 azimuth on the Clarke Spheroid of 1866:754 Latitude of Triangulation station Oahu west base: 211813.89 N, 755 Longitude of triangulation station Oahu west base: 157 50 55.79 W,756 Azimuth, triangulation station Oahu west base to triangulation station Oahu east757 base: 291 29 36.0 758 The Old Hawaiian datum is based on an adjusted latitude derived from a number759of astronomic latitudes in various parts of the island, and an astronomical longitude760obtained from observation lunar and Geodetic Survey Special No. 156, Triangulation in761Hawaii. (U.S Dept of Commerce, Special Publication 242, 1948) 762763Puerto Rico764 The geodetic datum which is defined by the following geographic position and765 azimuth on the Clarke Spheroid of 1866:766 Latitude of Triangulation Station Cordona Island Light House:175731.400 N767 Longitude of Triangulation Station Cordona Island Light House:663807.537 W131 xxxi 132Federal Geographic Data Committee FGDC Document Number XX 133National Shoreline Data Content Standard, Committee Review Draft, January 2007 134______768 Azimuth Triangulation station Cardona Island Light House to triangulation station769 Ponce southwest base: 128 36 26.2770Adopted in 1901or soon thereafter, the Puerto Rico datum is derived from observations771on the Island of Puerto Rico and the Virgin Islands. See U.S. Coast and Geodetic Survey772Field Engineers Bulletin, December 1938, page 22. (U.S Dept of Commerce, Special773Publication 242, 1948)774775Other - Other sources of information not listed in this domain would be sourced 776utilizing this field. 7777786.1.3 Informative Appendix 3: Shoreline_Definition_Domain 779780Shoreline (coastline) – The intersection of the land with the water surface. The shoreline781shown on charts represents the line of contact between the land and a selected water782elevation. In areas affected by tidal fluctuations, this line of contact is the mean high783water line. In confined coastal waters of diminished tidal influence, the mean water level784line may be used. (Hicks 1984)785786Shoreline – The line of contact between the land and a body of water. On Coast and 787Geodetic Survey nautical charts and surveys the shoreline approximates the mean high 788water line. In Coast Survey usage the term is considered synonymous with coastline. 789(Shalowitz, 1964)790135 xxxii 136Federal Geographic Data Committee FGDC Document Number XX 137National Shoreline Data Content Standard, Committee Review Draft, January 2007 138______791User Defined – Shoreline definitions as defined by the shoreline data developer.792793Other – Shoreline definitions, legal, technical, and scientific that are not listed in this794domain.7957966.1.4 Informative Appendix 4: Boundary_Reference_Domain 797798Baseline – The line from which maritime zone are measured. The normal baseline for799 measuring the territorial sea (TS), contiguous zone (CZ), exclusive economic800 zone (EEZ), and continental shelf is the low-water line along the coast.801802Submerged Lands Act – Federal Legislation that granted to the coastal states federal 803 rights to natural resources within 3 nautical miles (up to 9 miles for Texas and the804 Gulf coast of Florida) of the coast line. 43 U.S.C 1301 et seq.805806Seaward State Boundary - The limit of the state's jurisdictions under the Submerged807 Lands Act (SLA). Although many exceptions exist, the land and resources808 between the ordinary high water mark and the state seaward boundary (SSB) are809 generally held in trust by the coastal state for the benefit of the public (CSO810 1997).811812Revenue Sharing - Provided for states to claim an equitable share of revenues when a813 federal lease is within three miles of the territorial sea boundary. The amendments814 mandate that 27 percent of all revenues from production within three miles 139 xxxiii 140Federal Geographic Data Committee FGDC Document Number XX 141National Shoreline Data Content Standard, Committee Review Draft, January 2007 142______815 seaward of the federal/state boundary is to be given to the states. Zone extends 3 816 nautical miles beyond the state seaward limit. Also referred to as the Limit of the 817 "8(g) Zone".818819Territorial Sea – The offshore belt in which a coastal state has exclusive jurisdiction. The820 territorial sea may not extend more than 12 nautical miles from the coast line.821822Contiguous Zone – A zone seaward of the territorial sea in which coastal states may823 assert jurisdiction short of complete sovereignty. Article 24 of the Convention on824 the Territorial Sea and the Contiguous Zone authorizes such a zone “to prevent825 infringement of its customs, fiscal, immigration or sanitary regulations in territory826 or territorial sea….” Under the Convention the contiguous zone may extend no827 more than 12 miles from the coastline. See also: 1982 Law of the Sea828 Convention, Article 33.829830Continental Shelf Limit - Article 76 of the United Nations Convention on the Law of the831 Sea (UNCLOS) provides a definition and a detailed formula for determining the832 limit of the continental shelf beyond 200 nautical miles. Consistent with Article833 76 of UNCLOS and the 1958 Convention on the Continental Shelf, the U.S.834 continental shelf is comprised of the sea-bed and subsoil of the submarine areas835 that extend beyond its territorial sea throughout the natural prolongation of its836 land territory to the outer edge of the continental margin, including that portion837 beyond 200 nautical miles from the baseline. Under international law, the143 xxxiv 144Federal Geographic Data Committee FGDC Document Number XX 145National Shoreline Data Content Standard, Committee Review Draft, January 2007 146______838 continental shelf is defined to include the sea-bed and subsoil beyond the839 continental margin out to a distance of 200 nautical miles from the baseline. The840 U.S. has sovereign rights and exclusive jurisdiction over the exploration and841 exploitation of the continental shelf.842843Exclusive Economic Zone - The zone or area beyond and adjacent to the territorial sea. In844 this area, the U.S., like other coastal nations, has sovereign rights and exclusive845 jurisdiction to protect and manage its natural resources, including any economic846 development. The seaward limit of the EEZ is generally 200 nautical miles from847 the baseline. The U.S. does not have sovereignty in the EEZ as it does in its848 territory. Foreign vessels and nationals maintain the high seas freedoms or rights849 of navigation and over flight in the EEZ, as well as the right to lay and maintain850 submarine cables and pipelines. However, such rights are still subject to851 regulation by the U.S. in accordance with international law, including UNCLOS.852853Offshore Lease Blocks - An offshore cadastre that defines approved subdivisions of the 854 outer continental shelf (OCS) within federal jurisdiction.855856International Maritime Boundaries - The U.S. continental shelf and exclusive economic 857 zone (EEZ) claims cover approximately three million square miles of ocean858 space. Overlapping boundaries with other nations exist in 25 situations.859 International maritime boundaries are those agreed upon by one or more countries860 to resolve these overlapping claim issues.147 xxxv 148Federal Geographic Data Committee FGDC Document Number XX 149National Shoreline Data Content Standard, Committee Review Draft, January 2007 150______861862National Marine Sanctuary Boundaries - National Marine Sanctuaries Act (16 U.S.C. §§8631431 et seq.); Code of Federal Regulations (15 C.F.R. 922.41).864865National Estuarine Research Reserve System Boundaries - Coastal Zone Management866Act, as amended, sec. 315 (16 U.S.C. § 1461).8678686.1.5 Informative Appendix 5: Legal Status Domain 869870Ambulatory – Not Stationary. Baselines from which maritime boundaries are measured871 ambulate with accretion and erosion causing ambulation of the boundaries872 themselves.873874Tidal – For water to be tidal it does not necessarily have to be salty; it must have tides875 that regularly flow and reflow.876877Disputed – A conflict or controversy; a conflict of claims or rights; an assertion of a right,878 claim or demand on one side, met by contrary claims or allegations on the other.879 The subject of litigation; that matter for which a suit is brought and upon which880 issue is joined, and in relation to which juror areca and witnesses examined. 881882Adjudicated – To settle in the exercise of judicial authority. To determine finally.883884Connecting Line - Connecting Line indicates if the Record Boundary is part of a Parcel 151 xxxvi 152Federal Geographic Data Committee FGDC Document Number XX 153National Shoreline Data Content Standard, Committee Review Draft, January 2007 154______885 or a Legal Area Description or if the Record Boundary is a line connecting the886 Parcel or Legal Area Description to a Corner Point.887888Duplicate – To copy exactly; A reproduction of an original document having the same 889 particulars and effect as the original.8908916.1.6 Informative Appendix 6: Source Type Domain 892893Air Photo –Remotely Sensed data collected by an airborne platform.894895LIDAR – Airborne Light Detection and Ranging derived data.896897Land Survey – This aspect includes GPS surveying and conventional surveying.898899Modeled – Mathematically derived shoreline data.900901NOAA Chart – The shoreline as cartographically depicted from officially published 902 NOAA marine charts.903904USGS Topographic Sheet - The shoreline as cartographically depicted from officially 905 published topographic sheets from USGS.906907T-sheet - A special-use coastal survey topographic map produced by the NOAA National 155 xxxvii 156Federal Geographic Data Committee FGDC Document Number XX 157National Shoreline Data Content Standard, Committee Review Draft, January 2007 158______908 Geodetic Survey. T-sheets define the U.S. shoreline, including alongshore natural 909 and manmade features. These maps, ranging in scale from 1:5,000 to 1:40,000, 910 are carefully controlled for tide fluxes (standardized to mean low water) and 911 represent the most accurate delineation of shoreline in the nation.912913Other Manuscript – Provides for description of shoreline sources not listed in this914 domain.915916User Defined – Other sources of information not listed in this domain would be sourced 917 utilizing this field.9186.1.7 Informative Appendix 7: Classification System Domain 919920 Provides lists of known shoreline classifications. Though no shoreline921classification standard currently exists, the list provided were found to be most922prevalently used within the shoreline community. 923924Environmental Sensitivity Index, ESI925Army Corp of Engineers926National Wetlands Inventory927User Defined9286.1.8 Informative Appendix 8: Ellipsoidal_Type_Domain 929World Geodetic System 84 930 931 WGS 84 is the World Geodetic System of 1984. It is the reference frame used by 932 the U.S. Department of Defense (DoD) and is defined by the National Geospatial-159 xxxviii 160Federal Geographic Data Committee FGDC Document Number XX 161National Shoreline Data Content Standard, Committee Review Draft, January 2007 162______933 Intelligence Agency(NGA) (formerly the National Imagry and Mapping Agency) 934 (formerly the Defense Mapping Agency). WGS 84 is used by DoD for all its 935 mapping, charting, surveying, and navigation needs, including its GPS 936 "broadcast" and "precise" orbits. WGS 84 was defined in January 1987 using 937 Doppler satellite surveying techniques. It was used as the reference frame for 938 broadcast GPS Ephemerides (orbits) beginning January 23, 1987. At 0000 GMT 939 January 2, 1994, WGS 84 was upgraded in accuracy using GPS measurements. 940 The formal name then became WGS 84 (G730) since the upgrade date coincided 941 with the start of GPS Week 730. It became the reference frame for broadcast 942 orbits on June 28, 1994. At 0000 GMT September 30, 1996 (the start of GPS 943 Week 873), WGS 84 was redefined again and was more closely aligned with 944 International Earth Rotation Service (IERS) Terrestrial Reference Frame (ITRF) 945 94. It is now formally called WGS 84 (G873). WGS 84 (G873) was adopted as 946 the reference frame for broadcast orbits on January 29, 1997.9476.1.9 Informative Appendix 9: Orthometric_Type_Domain 948North American Vertical Datum 88 949 950 The North American Vertical Datum of 1988 (NAVD 88) is the vertical control 951 datum established in 1991 by the minimum-constraint adjustment of the 952 Canadian-Mexican-U.S. leveling observations. It held fixed the height of the 953 primary tidal bench mark, referenced to the new International Great Lakes Datum 954 of 1985 local mean sea level height value, at Father Point/Rimouski, Quebec, 955 Canada. Additional tidal bench mark elevations were not used due to the 956 demonstrated variations in sea surface topography, i.e., the fact that mean sea 957 level is not the same equipotential surface at all tidal bench marks. ("Results of 958 the General Adjustment of the North American Datum of 1988," Surveying and 959 Land Information Systems Vol. 52, No. 3, 1992 pp. 133-149) 960 961National Geodetic Vertical Datum of 1929 962 963 "The National Geodetic Vertical Datum of 1929: The name, after May 10, 1973, 964 of (the) Sea Level Datum of 1929." (Geodetic Glossary, pp. 57) 965 "Sea Level Datum of 1929: A vertical control datum established for vertical 966 control in the United States by the general adjustment of 1929." 967 968Other – Orthometric based datum types not defined in this domain. 969163 xxxix

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